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  • mongodb java driver - raw command?

    - by Scott
    Is it possible to execute raw commands as javascript through the Java driver for MongoDB? I'm tired of wrapping everything in Java objects using Rhino, and would happily sacrifice performance for the convenience of passing javascript directly through to the DB. If not, I can always use sleepymongoose or something, but I don't really want to add yet another language (python) to the stack at this point. Any insights are appreciated.

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  • Copying a file with PHP Command

    - by Tom
    Hi, I'm having a problem using the copy function in PHP, what is wrong with it? I get the error; Parse error: syntax error, unexpected T_VARIABLE On the bottom line; $targetDir = 'file.txt'; $targetDir2 = 'file2.txt'; copy($targetDir, $targetDir2); Thanks The entire file is; <?PHP $targetDir = 'file.txt'; $targetDir2 = 'file2.txt'; copy($targetDir, $targetDir2); ?> copy and pasted from the doc.

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  • Ant command line arguments

    - by js7354
    Program works fine when run with eclipse run configurations, but when run with ant, it is unable to parse int from args[0], which I do not understand. Full code is available here https://gist.github.com/4108950/e984a581d5e9de889eaf0c8faf0e57752e825a97 I believe it has something to do with ant, target name="run" description="run the project"> java dir="${build.dir}" classname="BinarySearchTree" fork="yes"> <arg value="6 in.txt"/> /java> /target> the arg value will be changed via the -D flag, as in ant -Dargs="6 testData1.txt" run. Any help would be much appreciated, it is very frustrating.

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  • command&pointer&malloc [closed]

    - by gcc
    input 23 3 4 4 42 n 23 0 9 9 n n n 3 9 9 x //according to input,i should create int pointer arrays. pointer arrays starting from 1 (that is initial arrays is arrays[1].when program sees n ,it must be jumb to arrays 2 expected output arrays[1] 3 4 5 42 arrays[2] 23 0 9 9 arrays[5] 3 9 9 x is stopper n is comman to create new pointer array i am new in this site anyone help me how can i write

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  • PHP shell command

    - by DGT
    Can anyone please tell me how to move file(s) into a dir in PHP? I did the following and it doesn't work. exec("temp/$file ../public/"); I would appreciate it.

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  • How to temporarily save the result of the query, to use in another?

    - by Truth
    I have this problem I think you may help me with. P.S. I'm not sure how to call this, so if anyone finds a more appropriate title, please do edit. Background I'm making this application for searching bus transit lines. Bus lines are a 3 digit number, and is unique and will never change. The requirement is to be able to search for lines from stop A to stop B. The user interface is already successful in hinting the user to only use valid stop names. The requirement is to be able to display if a route has a direct line, and if not, display a 2-line and even 3-line combination. Example: I need to get from point A to point D. The program should show: If there's a direct line A-D. If not, display alternative, 2 line combos, such as A-C, C-D. If there aren't any 2-line combos, search for 3-line combos: A-B, B-C, C-D. Of course, the app should display bus line numbers, as well as when to switch buses. What I have: My database is structured as follows (simplified, actual database includes locations and times and whatnot): +-----------+ | bus_stops | +----+------+ | id | name | +----+------+ +-------------------------------+ | lines_stops_relationship | +-------------+---------+-------+ | bus_line | stop_id | order | +-------------+---------+-------+ Where lines_stops_relationship describe a many-to-many relationship between the bus lines and the stops. Order, signifies the order in which stops appear in a single line. Not all lines go back and forth, and order has meaning (point A with order 2 comes after point B with order 1). The Problem We find out if a line can pass through the route easily enough. Just search for a single line which passes through both points in the correct order. How can I find if there's a 2/3 line combo? I was thinking to search for a line which matches the source stop, and one for the destination stop, and see if I can get a common stop between them, where the user can switch buses. How do I remember that stop? 3 line combo is even trickier, I find a line for the source, and a line for the destination, and then what? Search for a line which has 2 stops I guess, but again, How do I remember the stops? tl;dr How do I remember results from a query to be able to use it again? I'm hoping to achieve this in a single query (for each, a query for 1-line routes, a query for 2, and a query for 3-line combos). Note: I don't mind if someone suggests a completely different approach than what I have, I'm open to any solutions. Will award any assistance with a cookie and an upvote. Thanks in advance!

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  • [cakephp] problem with find query

    - by luk4s
    Hi I have a problem with find query: $userInProjects = $this->Timesheet->RegularPost->UserInProject->find('all', array('conditions' => array('UserInProject.user_id' => $id))); The result array: Array ( [0] => Array ( [UserInProject] => Array ( [id] => 11 [project_id] => 3 [position_id] => 1 [user_id] => 15 ) [Project] => Array ( [id] => 3 [short_name] => proj1 [full_name] => project 1 [start_date] => 2010-01-01 [end_date] => 2010-05-01 [agreement_number] => 12/34U/23 [active] => 1 [user_id] => 1 ) [Position] => Array ( [id] => 1 [name] => some_name ) [User] => Array ( [id] => 15 [username] => foo [first_name] => [last_name] => [email] => [email protected] [active] => 1 [created] => [modified] => ) [RegularPost] => Array ( [0] => Array ( [id] => 792 [date] => 2010-01-01 [size] => 0.20000 [users_in_project_id] => 11 ) [1] => Array ( [id] => 793 [date] => 2010-02-01 [size] => 0.20000 [users_in_project_id] => 11 ) ( and many more ...) ) ) [1] => Array ( [UserInProject] => Array ( [id] => 20 [project_id] => 3 [position_id] => 2 [user_id] => 15 ) [Project] => Array ( [id] => 3 [short_name] => proj1 [full_name] => project 1 [start_date] => 2010-01-01 [end_date] => 2010-05-01 [agreement_number] => 12/34U/23 [active] => 1 [user_id] => 1 ) [Position] => Array ( [id] => 2 [name] => some_name2 ) [User] => Array ( [id] => 15 [username] => foo [first_name] => [last_name] => [email] => [email protected] [active] => 1 [created] => [modified] => ) [RegularPost] => Array ( [0] => Array ( [id] => 836 [date] => 2010-01-01 [size] => 0.2 [users_in_project_id] => 20 ) [1] => Array ( [id] => 837 [date] => 2010-02-01 [size] => 0.3 [users_in_project_id] => 20 ) [2] => Array ( [id] => 838 [date] => 2010-03-01 [size] => 0.3 [users_in_project_id] => 20 ) ( and many more ...) ) ) ) What I want to achive is the array like above but RegularPost with [date] = 2010-02-01 only. Is there any way to pass the date '2010-02-01' to the RegularPost in this query? This query doesn't work: $userInProjects = $this->Timesheet->RegularPost->UserInProject->find('all', array('conditions' => array('UserInProject.user_id' => $id, 'RegularPost.date' => '2010-02-01'))); 1054: Unknown column 'RegularPost.date' in 'where clause' Please help. :)

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  • Hard Disk DRDY error: is it a crash

    - by pranjal
    I am using IBM Thinkpad, 1.7GHz, 512 RAM with Linux Mint 9 installed. I have two partitions in addition to root. One of the partitions became read-only yesterday, after which I rebooted my system. It is extremely slow along with DRDY Error : Is my Hard disk crashed ? Error Log while booting. Differences between boot sector and its backup. failed command : READ DMA BMDMA : stat 0X25 ata 1.00 : status : { DRDY ERR } ata 1.00 : status :{ UNC } Buffer I/O error on logical device, logical block 65467 smartctl output for the partition: mint mint # smartctl -a /dev/sda1 smartctl version 5.38 [i686-pc-linux-gnu] Copyright (C) 2002-8 Bruce Allen Home page is http://smartmontools.sourceforge.net/ === START OF INFORMATION SECTION === Device Model: TOSHIBA MK4026GAX RoHS Serial Number: X5LY1623T Firmware Version: PA107E User Capacity: 40,007,761,920 bytes Device is: Not in smartctl database [for details use: -P showall] ATA Version is: 6 ATA Standard is: Exact ATA specification draft version not indicated Local Time is: Thu Feb 17 06:48:25 2011 UTC SMART support is: Available - device has SMART capability. SMART support is: Enabled === START OF READ SMART DATA SECTION === SMART overall-health self-assessment test result: PASSED General SMART Values: Offline data collection status: (0x84) Offline data collection activity was suspended by an interrupting command from host. Auto Offline Data Collection: Enabled. Self-test execution status: ( 0) The previous self-test routine completed without error or no self-test has ever been run. Total time to complete Offline data collection: ( 153) seconds. Offline data collection capabilities: (0x1b) SMART execute Offline immediate. Auto Offline data collection on/off support. Suspend Offline collection upon new command. Offline surface scan supported. Self-test supported. No Conveyance Self-test supported. No Selective Self-test supported. SMART capabilities: (0x0003) Saves SMART data before entering power-saving mode. Supports SMART auto save timer. Error logging capability: (0x01) Error logging supported. No General Purpose Logging support. Short self-test routine recommended polling time: ( 2) minutes. Extended self-test routine recommended polling time: ( 30) minutes. SMART Attributes Data Structure revision number: 16 Vendor Specific SMART Attributes with Thresholds: ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE 1 Raw_Read_Error_Rate 0x000b 100 100 050 Pre-fail Always - 0 2 Throughput_Performance 0x0005 100 100 050 Pre-fail Offline - 0 3 Spin_Up_Time 0x0027 100 100 001 Pre-fail Always - 310 4 Start_Stop_Count 0x0032 100 100 000 Old_age Always - 3968 5 Reallocated_Sector_Ct 0x0033 100 100 050 Pre-fail Always - 40 7 Seek_Error_Rate 0x000b 100 100 050 Pre-fail Always - 0 8 Seek_Time_Performance 0x0005 100 100 050 Pre-fail Offline - 0 9 Power_On_Hours 0x0032 082 082 000 Old_age Always - 7257 10 Spin_Retry_Count 0x0033 179 100 030 Pre-fail Always - 0 12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 3484 192 Power-Off_Retract_Count 0x0032 100 100 000 Old_age Always - 489 193 Load_Cycle_Count 0x0032 064 064 000 Old_age Always - 367150 194 Temperature_Celsius 0x0022 100 100 000 Old_age Always - 36 (Lifetime Min/Max 14/57) 196 Reallocated_Event_Count 0x0032 100 100 000 Old_age Always - 33 197 Current_Pending_Sector 0x0032 100 100 000 Old_age Always - 82 198 Offline_Uncorrectable 0x0030 100 100 000 Old_age Offline - 1 199 UDMA_CRC_Error_Count 0x0032 200 253 000 Old_age Always - 0 220 Disk_Shift 0x0002 100 100 000 Old_age Always - 101 222 Loaded_Hours 0x0032 085 085 000 Old_age Always - 6146 223 Load_Retry_Count 0x0032 100 100 000 Old_age Always - 0 224 Load_Friction 0x0022 100 100 000 Old_age Always - 0 226 Load-in_Time 0x0026 100 100 000 Old_age Always - 227 240 Head_Flying_Hours 0x0001 100 100 001 Pre-fail Offline - 0 SMART Error Log Version: 1 ATA Error Count: 2371 (device log contains only the most recent five errors) CR = Command Register [HEX] FR = Features Register [HEX] SC = Sector Count Register [HEX] SN = Sector Number Register [HEX] CL = Cylinder Low Register [HEX] CH = Cylinder High Register [HEX] DH = Device/Head Register [HEX] DC = Device Command Register [HEX] ER = Error register [HEX] ST = Status register [HEX] Powered_Up_Time is measured from power on, and printed as DDd+hh:mm:SS.sss where DD=days, hh=hours, mm=minutes, SS=sec, and sss=millisec. It "wraps" after 49.710 days. Error 2371 occurred at disk power-on lifetime: 7256 hours (302 days + 8 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 40 51 05 1a 1b 00 e0 Error: UNC 5 sectors at LBA = 0x00001b1a = 6938 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- c8 00 05 1a 1b 00 e0 00 00:03:10.061 READ DMA f8 00 00 00 00 00 e0 00 00:03:10.061 READ NATIVE MAX ADDRESS ec 00 00 00 00 00 a0 02 00:03:10.053 IDENTIFY DEVICE ef 03 45 00 00 00 a0 02 00:03:10.053 SET FEATURES [Set transfer mode] f8 00 00 00 00 00 e0 00 00:03:10.053 READ NATIVE MAX ADDRESS Error 2370 occurred at disk power-on lifetime: 7256 hours (302 days + 8 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 40 51 05 1a 1b 00 e0 Error: UNC 5 sectors at LBA = 0x00001b1a = 6938 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- c8 00 05 1a 1b 00 e0 00 00:03:03.328 READ DMA f8 00 00 00 00 00 e0 00 00:03:03.327 READ NATIVE MAX ADDRESS ec 00 00 00 00 00 a0 02 00:03:03.320 IDENTIFY DEVICE ef 03 45 00 00 00 a0 02 00:03:03.319 SET FEATURES [Set transfer mode] f8 00 00 00 00 00 e0 00 00:03:03.319 READ NATIVE MAX ADDRESS Error 2369 occurred at disk power-on lifetime: 7256 hours (302 days + 8 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 40 51 05 1a 1b 00 e0 Error: UNC 5 sectors at LBA = 0x00001b1a = 6938 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- c8 00 05 1a 1b 00 e0 00 00:02:56.582 READ DMA f8 00 00 00 00 00 e0 00 00:02:56.582 READ NATIVE MAX ADDRESS ec 00 00 00 00 00 a0 02 00:02:56.574 IDENTIFY DEVICE ef 03 45 00 00 00 a0 02 00:02:56.574 SET FEATURES [Set transfer mode] f8 00 00 00 00 00 e0 00 00:02:56.574 READ NATIVE MAX ADDRESS Error 2368 occurred at disk power-on lifetime: 7256 hours (302 days + 8 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 40 51 05 1a 1b 00 e0 Error: UNC 5 sectors at LBA = 0x00001b1a = 6938 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- c8 00 05 1a 1b 00 e0 00 00:02:49.809 READ DMA f8 00 00 00 00 00 e0 00 00:02:49.809 READ NATIVE MAX ADDRESS ec 00 00 00 00 00 a0 02 00:02:49.801 IDENTIFY DEVICE ef 03 45 00 00 00 a0 02 00:02:49.801 SET FEATURES [Set transfer mode] f8 00 00 00 00 00 e0 00 00:02:49.801 READ NATIVE MAX ADDRESS Error 2367 occurred at disk power-on lifetime: 7256 hours (302 days + 8 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 40 51 05 1a 1b 00 e0 Error: UNC 5 sectors at LBA = 0x00001b1a = 6938 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- c8 00 05 1a 1b 00 e0 00 00:02:43.056 READ DMA f8 00 00 00 00 00 e0 00 00:02:43.056 READ NATIVE MAX ADDRESS ec 00 00 00 00 00 a0 02 00:02:43.048 IDENTIFY DEVICE ef 03 45 00 00 00 a0 02 00:02:43.048 SET FEATURES [Set transfer mode] f8 00 00 00 00 00 e0 00 00:02:43.047 READ NATIVE MAX ADDRESS SMART Self-test log structure revision number 1 No self-tests have been logged. [To run self-tests, use: smartctl -t] Device does not support Selective Self Tests/Logging Do I need to get a new Hard Disk my PC ?

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  • MySql multiple selects batching in .net

    - by Amith George
    I have a situation in my application. For each x-axis point in my chart, I am plotting 5 y-axis values. To calculate each of these 5 values, I need to make 4 different queries. Ie, for each x-axis point I need to fire 20 sql queries. Now, I need to plot 40 such points in the my chart. Its resulting in a pathetic performance where it takes close to a minute to get all the data back from the database. Each of 4 different queries consists of a join between 2 tables. One has only 6 rows. The other close to 10,000. Each of the 4 queries has different WHERE clauses, so they are different queries. For each point in the x-axis, only the values for the where clauses change. I have tried combining each of the 4 queries into one big string. Basically batch the four selects. These are again batched for each y-axis value. So, for each x-axis point, I am now firing one big command that consists of 20 different select statements. Technically, I should be experiencing a big performance boost, right? Instead of hitting the db 40x5x4 = 800 times, I am now hitting it just 40 times. But instead of taking 60 seconds, it taking 50-55 seconds... not much of a help. I am using MySql 5.1, and the 6.1 version of its .Net connector. What can I do to improve the performance? Edit: One of the 4 queries is as follows: SELECT SUM(TIME_TO_SEC(TIMEDIFF(T1.col2, T1.col1))* T2.col1 / (3600 *1000)) AS TotalTime FROM Table T1 JOIN Table T2 ON T1.col3 = T2.col3 WHERE T1.col4 = 'i' AND T1.col1 >= '2009-12-25 00:00:00' AND T1.col2 <= '2009-12-26 00:00:00'; The other 3 queries are similar, only the where clause changes slightly. This set of 4 queries is fired 5 times. The first 3 times against the join of table T1 and T2, passing in different values for col4. And the next two times against the join of table T3 and T2 passing in different values for col4. These 5 values are the y-axis values for a particular x-axis point. The data returned by all these queries is the same format. so, we tried doing a UNION ALL on all these queries. No substantial difference. One strange thing, however, after indexing the foreign key on the table T1 [while it contained over a lakh records], the queries were using the index, but they had become slower. At times, the queries would take double the time to return the data.

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  • PHP will not delete from MySQL

    - by Michal Kopanski
    For some reason, JavaScript/PHP wont delete my data from MySQL! Here is the rundown of the problem. I have an array that displays all my MySQL entries in a nice format, with a button to delete the entry for each one individually. It looks like this: <?php include("login.php"); //connection to the database $dbhandle = mysql_connect($hostname, $username, $password) or die("<br/><h1>Unable to connect to MySQL, please contact support at [email protected]</h1>"); //select a database to work with $selected = mysql_select_db($dbname, $dbhandle) or die("Could not select database."); //execute the SQL query and return records if (!$result = mysql_query("SELECT `id`, `url` FROM `videos`")) echo 'mysql error: '.mysql_error(); //fetch tha data from the database while ($row = mysql_fetch_array($result)) { ?> <div class="video"><a class="<?php echo $row{'id'}; ?>" href="http://www.youtube.com/watch?v=<?php echo $row{'url'}; ?>">http://www.youtube.com/watch?v=<?php echo $row{'url'}; ?></a><a class="del" href="javascript:confirmation(<? echo $row['id']; ?>)">delete</a></div> <?php } //close the connection mysql_close($dbhandle); ?> The delete button has an href of javascript:confirmation(<? echo $row['id']; ?>) , so once you click on delete, it runs this: <script type="text/javascript"> <!-- function confirmation(ID) { var answer = confirm("Are you sure you want to delete this video?") if (answer){ alert("Entry Deleted") window.location = "delete.php?id="+ID; } else{ alert("No action taken") } } //--> </script> The JavaScript should theoretically pass the 'ID' onto the page delete.php. That page looks like this (and I think this is where the problem is): <?php include ("login.php"); mysql_connect($hostname, $username, $password) or die("Unable to connect to MySQL"); mysql_select_db ($dbname) or die("Unable to connect to database"); mysql_query("DELETE FROM `videos` WHERE `videos`.`id` ='.$id.'"); echo ("Video has been deleted."); ?> If there's anyone out there that may know the answer to this, I would greatly appreciate it. I am also opened to suggestions (for those who aren't sure). Thanks!

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  • Problem with Executing Mysql stored procedure

    - by karthik
    The stored procedure builds without any problem. The purpose of this is to take backup of selected tables to a script file. when the SP returns a value {Insert statements}. I am using the below MySql stored procedure, created by SQLWAYS [Tool to convert MsSql to MySql]. The actual MsSql SP is from http://www.codeproject.com/KB/database/InsertGeneratorPack.aspx When i execute the SP in MySql Query Browser, It says "Unknown column 'tbl_users' in 'field list'" What would be the problem ? Because there was no error when i build-ed this Converted MySql SP. Help.. DELIMITER $$ DROP PROCEDURE IF EXISTS `demo`.`InsertGenerator` $$ CREATE DEFINER=`root`@`localhost` PROCEDURE `InsertGenerator`(v_tableName VARCHAR(100)) SWL_return: BEGIN -- SQLWAYS_EVAL# to retrieve column specific information -- SQLWAYS_EVAL# table DECLARE v_string NATIONAL VARCHAR(3000); -- SQLWAYS_EVAL# first half -- SQLWAYS_EVAL# tement DECLARE v_stringData NATIONAL VARCHAR(3000); -- SQLWAYS_EVAL# data -- SQLWAYS_EVAL# statement DECLARE v_dataType NATIONAL VARCHAR(1000); -- SQLWAYS_EVAL# -- SQLWAYS_EVAL# columns DECLARE v_colName NATIONAL VARCHAR(50); DECLARE NO_DATA INT DEFAULT 0; DECLARE cursCol CURSOR FOR SELECT column_name,data_type FROM `columns` WHERE table_name = v_tableName; DECLARE CONTINUE HANDLER FOR SQLEXCEPTION BEGIN SET NO_DATA = -2; END; DECLARE CONTINUE HANDLER FOR NOT FOUND SET NO_DATA = -1; OPEN cursCol; SET v_string = CONCAT('INSERT ',v_tableName,'('); SET v_stringData = ''; SET NO_DATA = 0; FETCH cursCol INTO v_colName,v_dataType; IF NO_DATA <> 0 then -- NOT SUPPORTED print CONCAT('Table ',@tableName, ' not found, processing skipped.') close cursCol; LEAVE SWL_return; end if; WHILE NO_DATA = 0 DO IF v_dataType in('varchar','char','nchar','nvarchar') then SET v_stringData = CONCAT(v_stringData,'SQLWAYS_EVAL# ll(',v_colName,'SQLWAYS_EVAL# ''+'); ELSE if v_dataType in('text','ntext') then -- SQLWAYS_EVAL# -- SQLWAYS_EVAL# else SET v_stringData = CONCAT(v_stringData,'SQLWAYS_EVAL# ll(cast(',v_colName,'SQLWAYS_EVAL# 00)),'''')+'''''',''+'); ELSE IF v_dataType = 'money' then -- SQLWAYS_EVAL# doesn't get converted -- SQLWAYS_EVAL# implicitly SET v_stringData = CONCAT(v_stringData,'SQLWAYS_EVAL# y,''''''+ isnull(cast(',v_colName,'SQLWAYS_EVAL# 0)),''0.0000'')+''''''),''+'); ELSE IF v_dataType = 'datetime' then SET v_stringData = CONCAT(v_stringData,'SQLWAYS_EVAL# time,''''''+ isnull(cast(',v_colName, 'SQLWAYS_EVAL# 0)),''0'')+''''''),''+'); ELSE IF v_dataType = 'image' then SET v_stringData = CONCAT(v_stringData,'SQLWAYS_EVAL# ll(cast(convert(varbinary,',v_colName, 'SQLWAYS_EVAL# 6)),''0'')+'''''',''+'); ELSE SET v_stringData = CONCAT(v_stringData,'SQLWAYS_EVAL# ll(cast(',v_colName,'SQLWAYS_EVAL# 0)),''0'')+'''''',''+'); end if; end if; end if; end if; end if; SET v_string = CONCAT(v_string,v_colName,','); SET NO_DATA = 0; FETCH cursCol INTO v_colName,v_dataType; END WHILE; END $$ DELIMITER ;

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  • GROUP BY and SUM distinct date across 2 tables

    - by kenitech
    I'm not sure if this is possible in one mysql query so I might just combine the results via php. I have 2 tables: 'users' and 'billing' I'm trying to group summed activity for every date that is available in these two tables. 'users' is not historical data but 'billing' contains a record for each transaction. In this example I am showing a user's status which I'd like to sum for created date and deposit amounts that I would also like to sum by created date. I realize there is a bit of a disconnect between the data but I'd like to some all of it together and display it as seen below. This will show me an overview of all of the users by when they were created and what the current statuses are next to total transactions. I've tried UNION as well as LEFT JOIN but I can't seem to get either to work. Union example is pretty close but doesn't combine the dates into one row. ( SELECT created, SUM(status) as totalActive, NULL as totalDeposit FROM users GROUP BY created ) UNION ( SELECT created, NULL as totalActive, SUM(transactionAmount) as totalDeposit FROM billing GROUP BY created ) I've also tried using a date lookup table and joining on the dates but the SUM values are being added multiple times. note: I don't care about the userIds at all but have it in here for the example. users table (where status of '1' denotes "active") (one record for each user) created | userId | status 2010-03-01 | 10 | 0 2010-03-01 | 11 | 1 2010-03-01 | 12 | 1 2010-03-10 | 13 | 0 2010-03-12 | 14 | 1 2010-03-12 | 15 | 1 2010-03-13 | 16 | 0 2010-03-15 | 17 | 1 billing table (record created for every instance of a billing "transaction" created | userId | transactionAmount 2010-03-01 | 10 | 50 2010-03-01 | 18 | 50 2010-03-01 | 19 | 100 2010-03-10 | 89 | 55 2010-03-15 | 16 | 50 2010-03-15 | 12 | 90 2010-03-22 | 99 | 150 desired result: created | sumStatusActive | sumStatusInactive | sumTransactions 2010-03-01 | 2 | 1 | 200 2010-03-10 | 0 | 1 | 55 2010-03-12 | 2 | 0 | 0 2010-03-13 | 0 | 0 | 0 2010-03-15 | 1 | 0 | 140 2010-03-22 | 0 | 0 | 150 Table dump: CREATE TABLE IF NOT EXISTS `users` ( `created` date NOT NULL, `userId` int(11) NOT NULL, `status` smallint(6) NOT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1; INSERT INTO `users` (`created`, `userId`, `status`) VALUES ('2010-03-01', 10, 0), ('2010-03-01', 11, 1), ('2010-03-01', 12, 1), ('2010-03-10', 13, 0), ('2010-03-12', 14, 1), ('2010-03-12', 15, 1), ('2010-03-13', 16, 0), ('2010-03-15', 17, 1); CREATE TABLE IF NOT EXISTS `billing` ( `created` date NOT NULL, `userId` int(11) NOT NULL, `transactionAmount` int(11) NOT NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1; INSERT INTO `billing` (`created`, `userId`, `transactionAmount`) VALUES ('2010-03-01', 10, 50), ('2010-03-01', 18, 50), ('2010-03-01', 19, 100), ('2010-03-10', 89, 55), ('2010-03-15', 16, 50), ('2010-03-15', 12, 90), ('2010-03-22', 99, 150);

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  • Basics of Join Predicate Pushdown in Oracle

    - by Maria Colgan
    Happy New Year to all of our readers! We hope you all had a great holiday season. We start the new year by continuing our series on Optimizer transformations. This time it is the turn of Predicate Pushdown. I would like to thank Rafi Ahmed for the content of this blog.Normally, a view cannot be joined with an index-based nested loop (i.e., index access) join, since a view, in contrast with a base table, does not have an index defined on it. A view can only be joined with other tables using three methods: hash, nested loop, and sort-merge joins. Introduction The join predicate pushdown (JPPD) transformation allows a view to be joined with index-based nested-loop join method, which may provide a more optimal alternative. In the join predicate pushdown transformation, the view remains a separate query block, but it contains the join predicate, which is pushed down from its containing query block into the view. The view thus becomes correlated and must be evaluated for each row of the outer query block. These pushed-down join predicates, once inside the view, open up new index access paths on the base tables inside the view; this allows the view to be joined with index-based nested-loop join method, thereby enabling the optimizer to select an efficient execution plan. The join predicate pushdown transformation is not always optimal. The join predicate pushed-down view becomes correlated and it must be evaluated for each outer row; if there is a large number of outer rows, the cost of evaluating the view multiple times may make the nested-loop join suboptimal, and therefore joining the view with hash or sort-merge join method may be more efficient. The decision whether to push down join predicates into a view is determined by evaluating the costs of the outer query with and without the join predicate pushdown transformation under Oracle's cost-based query transformation framework. The join predicate pushdown transformation applies to both non-mergeable views and mergeable views and to pre-defined and inline views as well as to views generated internally by the optimizer during various transformations. The following shows the types of views on which join predicate pushdown is currently supported. UNION ALL/UNION view Outer-joined view Anti-joined view Semi-joined view DISTINCT view GROUP-BY view Examples Consider query A, which has an outer-joined view V. The view cannot be merged, as it contains two tables, and the join between these two tables must be performed before the join between the view and the outer table T4. A: SELECT T4.unique1, V.unique3 FROM T_4K T4,            (SELECT T10.unique3, T10.hundred, T10.ten             FROM T_5K T5, T_10K T10             WHERE T5.unique3 = T10.unique3) VWHERE T4.unique3 = V.hundred(+) AND       T4.ten = V.ten(+) AND       T4.thousand = 5; The following shows the non-default plan for query A generated by disabling join predicate pushdown. When query A undergoes join predicate pushdown, it yields query B. Note that query B is expressed in a non-standard SQL and shows an internal representation of the query. B: SELECT T4.unique1, V.unique3 FROM T_4K T4,           (SELECT T10.unique3, T10.hundred, T10.ten             FROM T_5K T5, T_10K T10             WHERE T5.unique3 = T10.unique3             AND T4.unique3 = V.hundred(+)             AND T4.ten = V.ten(+)) V WHERE T4.thousand = 5; The execution plan for query B is shown below. In the execution plan BX, note the keyword 'VIEW PUSHED PREDICATE' indicates that the view has undergone the join predicate pushdown transformation. The join predicates (shown here in red) have been moved into the view V; these join predicates open up index access paths thereby enabling index-based nested-loop join of the view. With join predicate pushdown, the cost of query A has come down from 62 to 32.  As mentioned earlier, the join predicate pushdown transformation is cost-based, and a join predicate pushed-down plan is selected only when it reduces the overall cost. Consider another example of a query C, which contains a view with the UNION ALL set operator.C: SELECT R.unique1, V.unique3 FROM T_5K R,            (SELECT T1.unique3, T2.unique1+T1.unique1             FROM T_5K T1, T_10K T2             WHERE T1.unique1 = T2.unique1             UNION ALL             SELECT T1.unique3, T2.unique2             FROM G_4K T1, T_10K T2             WHERE T1.unique1 = T2.unique1) V WHERE R.unique3 = V.unique3 and R.thousand < 1; The execution plan of query C is shown below. In the above, 'VIEW UNION ALL PUSHED PREDICATE' indicates that the UNION ALL view has undergone the join predicate pushdown transformation. As can be seen, here the join predicate has been replicated and pushed inside every branch of the UNION ALL view. The join predicates (shown here in red) open up index access paths thereby enabling index-based nested loop join of the view. Consider query D as an example of join predicate pushdown into a distinct view. We have the following cardinalities of the tables involved in query D: Sales (1,016,271), Customers (50,000), and Costs (787,766).  D: SELECT C.cust_last_name, C.cust_city FROM customers C,            (SELECT DISTINCT S.cust_id             FROM sales S, costs CT             WHERE S.prod_id = CT.prod_id and CT.unit_price > 70) V WHERE C.cust_state_province = 'CA' and C.cust_id = V.cust_id; The execution plan of query D is shown below. As shown in XD, when query D undergoes join predicate pushdown transformation, the expensive DISTINCT operator is removed and the join is converted into a semi-join; this is possible, since all the SELECT list items of the view participate in an equi-join with the outer tables. Under similar conditions, when a group-by view undergoes join predicate pushdown transformation, the expensive group-by operator can also be removed. With the join predicate pushdown transformation, the elapsed time of query D came down from 63 seconds to 5 seconds. Since distinct and group-by views are mergeable views, the cost-based transformation framework also compares the cost of merging the view with that of join predicate pushdown in selecting the most optimal execution plan. Summary We have tried to illustrate the basic ideas behind join predicate pushdown on different types of views by showing example queries that are quite simple. Oracle can handle far more complex queries and other types of views not shown here in the examples. Again many thanks to Rafi Ahmed for the content of this blog post.

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  • git post-receive hook throws "command not found" error but seems to run properly and no errors when run manually

    - by Ben
    I have a post-receive hook that runs on a central git repository set up with gitolite to trigger a git pull on a staging server. It seems to work properly, but throws a "command not found" error when it is run. I am trying to track down the source of the error, but have not had any luck. Running the same commands manually does not produce an error. The error changes depending on what was done in the commit that is being pushed to the central repository. For instance, if 'git rm ' was committed and pushed to the central repo the error message will be "remote: hooks/post-receive: line 16: Removed: command not found" and if 'git add ' was committed and pushed to the central repo the error message will be "remote: hooks/post-receive: line 16: Merge: command not found". In either case the 'git pull' run on the staging server works correctly despite the error message. Here is the post-receive script: #!/bin/bash # # This script is triggered by a push to the local git repository. It will # ssh into a remote server and perform a git pull. # # The SSH_USER must be able to log into the remote server with a # passphrase-less SSH key *AND* be able to do a git pull without a passphrase. # # The command to actually perform the pull request on the remost server comes # from the ~/.ssh/authorized_keys file on the REMOTE_HOST and is triggered # by the ssh login. SSH_USER="remoteuser" REMOTE_HOST="staging.server.com" `ssh $SSH_USER@$REMOTE_HOST` # This is line 16 echo "Done!" The command that does the git pull on the staging server is in the ssh user's ~/.ssh/authorized_keys file and is: command="cd /var/www/staging_site; git pull",no-port-forwarding,no-X11-forwarding,no-agent-forwarding, ssh-rsa AAAAB3NzaC1yc2EAAAABIwAA... (the rest of the public key) This is the actual output from removing a file from my local repo, committing it locally, and pushing it to the central git repo: ben@tamarack:~/thejibe/testing/web$ git rm ./testing rm 'testing' ben@tamarack:~/thejibe/testing/web$ git commit -a -m "Remove testing file" [master bb96e13] Remove testing file 1 files changed, 0 insertions(+), 5 deletions(-) delete mode 100644 testing ben@tamarack:~/thejibe/testing/web$ git push Counting objects: 3, done. Delta compression using up to 2 threads. Compressing objects: 100% (2/2), done. Writing objects: 100% (2/2), 221 bytes, done. Total 2 (delta 1), reused 0 (delta 0) remote: From [email protected]:testing remote: aa72ad9..bb96e13 master -> origin/master remote: hooks/post-receive: line 16: Removed: command not found # The error msg remote: Done! To [email protected]:testing aa72ad9..bb96e13 master -> master ben@tamarack:~/thejibe/testing/web$ As you can see the post-receive script gets to the echo "Done!" line and when I look on the staging server the git pull has been successfully run, but there's still that nagging error message. Any suggestions on where to look for the source of the error message would be greatly appreciated. I'm tempted to redirect stderr to /dev/null but would prefer to know what the problem is.

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  • git post-receive hook throws "command not found" error but seems to run properly and no errors when run manually

    - by Ben
    I have a post-receive hook that runs on a central git repository set up with gitolite to trigger a git pull on a staging server. It seems to work properly, but throws a "command not found" error when it is run. I am trying to track down the source of the error, but have not had any luck. Running the same commands manually does not produce an error. The error changes depending on what was done in the commit that is being pushed to the central repository. For instance, if 'git rm ' was committed and pushed to the central repo the error message will be "remote: hooks/post-receive: line 16: Removed: command not found" and if 'git add ' was committed and pushed to the central repo the error message will be "remote: hooks/post-receive: line 16: Merge: command not found". In either case the 'git pull' run on the staging server works correctly despite the error message. Here is the post-receive script: #!/bin/bash # # This script is triggered by a push to the local git repository. It will # ssh into a remote server and perform a git pull. # # The SSH_USER must be able to log into the remote server with a # passphrase-less SSH key *AND* be able to do a git pull without a passphrase. # # The command to actually perform the pull request on the remost server comes # from the ~/.ssh/authorized_keys file on the REMOTE_HOST and is triggered # by the ssh login. SSH_USER="remoteuser" REMOTE_HOST="staging.server.com" `ssh $SSH_USER@$REMOTE_HOST` # This is line 16 echo "Done!" The command that does the git pull on the staging server is in the ssh user's ~/.ssh/authorized_keys file and is: command="cd /var/www/staging_site; git pull",no-port-forwarding,no-X11-forwarding,no-agent-forwarding, ssh-rsa AAAAB3NzaC1yc2EAAAABIwAA... (the rest of the public key) This is the actual output from removing a file from my local repo, committing it locally, and pushing it to the central git repo: ben@tamarack:~/thejibe/testing/web$ git rm ./testing rm 'testing' ben@tamarack:~/thejibe/testing/web$ git commit -a -m "Remove testing file" [master bb96e13] Remove testing file 1 files changed, 0 insertions(+), 5 deletions(-) delete mode 100644 testing ben@tamarack:~/thejibe/testing/web$ git push Counting objects: 3, done. Delta compression using up to 2 threads. Compressing objects: 100% (2/2), done. Writing objects: 100% (2/2), 221 bytes, done. Total 2 (delta 1), reused 0 (delta 0) remote: From [email protected]:testing remote: aa72ad9..bb96e13 master -> origin/master remote: hooks/post-receive: line 16: Removed: command not found # The error msg remote: Done! To [email protected]:testing aa72ad9..bb96e13 master -> master ben@tamarack:~/thejibe/testing/web$ As you can see the post-receive script gets to the echo "Done!" line and when I look on the staging server the git pull has been successfully run, but there's still that nagging error message. Any suggestions on where to look for the source of the error message would be greatly appreciated. I'm tempted to redirect stderr to /dev/null but would prefer to know what the problem is.

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  • Entity Framework version 1- Brief Synopsis and Tips &ndash; Part 1

    - by Rohit Gupta
    To Do Eager loading use Projections (for e.g. from c in context.Contacts select c, c.Addresses)  or use Include Query Builder Methods (Include(“Addresses”)) If there is multi-level hierarchical Data then to eager load all the relationships use Include Query Builder methods like customers.Include("Order.OrderDetail") to include Order and OrderDetail collections or use customers.Include("Order.OrderDetail.Location") to include all Order, OrderDetail and location collections with a single include statement =========================================================================== If the query uses Joins then Include() Query Builder method will be ignored, use Nested Queries instead If the query does projections then Include() Query Builder method will be ignored Use Address.ContactReference.Load() OR Contact.Addresses.Load() if you need to Deferred Load Specific Entity – This will result in extra round trips to the database ObjectQuery<> cannot return anonymous types... it will return a ObjectQuery<DBDataRecord> Only Include method can be added to Linq Query Methods Any Linq Query method can be added to Query Builder methods. If you need to append a Query Builder Method (other than Include) after a LINQ method  then cast the IQueryable<Contact> to ObjectQuery<Contact> and then append the Query Builder method to it =========================================================================== Query Builder methods are Select, Where, Include Methods which use Entity SQL as parameters e.g. "it.StartDate, it.EndDate" When Query Builder methods do projection then they return ObjectQuery<DBDataRecord>, thus to iterate over this collection use contact.Item[“Name”].ToString() When Linq To Entities methods do projection, they return collection of anonymous types --- thus the collection is strongly typed and supports Intellisense EF Object Context can track changes only on Entities, not on Anonymous types. If you use a Defining Query for a EntitySet then the EntitySet becomes readonly since a Defining Query is the same as a View (which is treated as a ReadOnly by default). However if you want to use this EntitySet for insert/update/deletes then we need to map stored procs (as created in the DB) to the insert/update/delete functions of the Entity in the Designer You can use either Execute method or ToList() method to bind data to datasources/bindingsources If you use the Execute Method then remember that you can traverse through the ObjectResult<> collection (returned by Execute) only ONCE. In WPF use ObservableCollection to bind to data sources , for keeping track of changes and letting EF send updates to the DB automatically. Use Extension Methods to add logic to Entities. For e.g. create extension methods for the EntityObject class. Create a method in ObjectContext Partial class and pass the entity as a parameter, then call this method as desired from within each entity. ================================================================ DefiningQueries and Stored Procedures: For Custom Entities, one can use DefiningQuery or Stored Procedures. Thus the Custom Entity Collection will be populated using the DefiningQuery (of the EntitySet) or the Sproc. If you use Sproc to populate the EntityCollection then the query execution is immediate and this execution happens on the Server side and any filters applied will be applied in the Client App. If we use a DefiningQuery then these queries are composable, meaning the filters (if applied to the entityset) will all be sent together as a single query to the DB, returning only filtered results. If the sproc returns results that cannot be mapped to existing entity, then we first create the Entity/EntitySet in the CSDL using Designer, then create a dummy Entity/EntitySet using XML in the SSDL. When creating a EntitySet in the SSDL for this dummy entity, use a TSQL that does not return any results, but does return the relevant columns e.g. select ContactID, FirstName, LastName from dbo.Contact where 1=2 Also insure that the Entity created in the SSDL uses the SQL DataTypes and not .NET DataTypes. If you are unable to open the EDMX file in the designer then note the Errors ... they will give precise info on what is wrong. The Thrid option is to simply create a Native Query in the SSDL using <Function Name="PaymentsforContact" IsComposable="false">   <CommandText>SELECT ActivityId, Activity AS ActivityName, ImagePath, Category FROM dbo.Activities </CommandText></FuncTion> Then map this Function to a existing Entity. This is a quick way to get a custom Entity which is regular Entity with renamed columns or additional columns (which are computed columns). The disadvantage to using this is that It will return all the rows from the Defining query and any filter (if defined) will be applied only at the Client side (after getting all the rows from DB). If you you DefiningQuery instead then we can use that as a Composable Query. The Fourth option (for mapping a READ stored proc results to a non-existent Entity) is to create a View in the Database which returns all the fields that the sproc also returns, then update the Model so that the model contains this View as a Entity. Then map the Read Sproc to this View Entity. The other option would be to simply create the View and remove the sproc altogether. ================================================================ To Execute a SProc that does not return a entity, use a EntityCommand to execute that proc. You cannot call a sproc FunctionImport that does not return Entities From Code, the only way is to use SSDL function calls using EntityCommand.  This changes with EntityFramework Version 4 where you can return Scalar Types, Complex Types, Entities or NonQuery ================================================================ UDF when created as a Function in SSDL, we need to set the Name & IsComposable properties for the Function element. IsComposable is always false for Sprocs, for UDF's set this to true. You cannot call UDF "Function" from within code since you cannot import a UDF Function into the CSDL Model (with Version 1 of EF). only stored procedures can be imported and then mapped to a entity ================================================================ Entity Framework requires properties that are involved in association mappings to be mapped in all of the function mappings for the entity (Insert, Update and Delete). Because Payment has an association to Reservation... hence we need to pass both the paymentId and reservationId to the Delete sproc even though just the paymentId is the PK on the Payment Table. ================================================================ When mapping insert, update and delete procs to a Entity, insure that all the three or none are mapped. Further if you have a base class and derived class in the CSDL, then you must map (ins, upd, del) sprocs to all parent and child entities in the inheritance relationship. Note that this limitation that base and derived entity methods must all must be mapped does not apply when you are mapping Read Stored Procedures.... ================================================================ You can write stored procedures SQL directly into the SSDL by creating a Function element in the SSDL and then once created, you can map this Function to a CSDL Entity directly in the designer during Function Import ================================================================ You can do Entity Splitting such that One Entity maps to multiple tables in the DB. For e.g. the Customer Entity currently derives from Contact Entity...in addition it also references the ContactPersonalInfo Entity. One can copy all properties from the ContactPersonalInfo Entity into the Customer Entity and then Delete the CustomerPersonalInfo entity, finall one needs to map the copied properties to the ContactPersonalInfo Table in Table Mapping (by adding another table (ContactPersonalInfo) to the Table Mapping... this is called Entity Splitting. Thus now when you insert a Customer record, it will automatically create SQL to insert records into the Contact, Customers and ContactPersonalInfo tables even though you have a Single Entity called Customer in the CSDL =================================================================== There is Table by Type Inheritance where another EDM Entity can derive from another EDM entity and absorb the inherted entities properties, for example in the Break Away Geek Adventures EDM, the Customer entity derives (inherits) from the Contact Entity and absorbs all the properties of Contact entity. Thus when you create a Customer Entity in Code and then call context.SaveChanges the Object Context will first create the TSQL to insert into the Contact Table followed by a TSQL to insert into the Customer table =================================================================== Then there is the Table per Hierarchy Inheritance..... where different types are created based on a condition (similar applying a condition to filter a Entity to contain filtered records)... the diference being that the filter condition populates a new Entity Type (derived from the base Entity). In the BreakAway sample the example is Lodging Entity which is a Abstract Entity and Then Resort and NonResort Entities which derive from Lodging Entity and records are filtered based on the value of the Resort Boolean field =================================================================== Then there is Table per Concrete Type Hierarchy where we create a concrete Entity for each table in the database. In the BreakAway sample there is a entity for the Reservation table and another Entity for the OldReservation table even though both the table contain the same number of fields. The OldReservation Entity can then inherit from the Reservation Entity and configure the OldReservation Entity to remove all Scalar Properties from the Entity (since it inherits the properties from Reservation and filters based on ReservationDate field) =================================================================== Complex Types (Complex Properties) Entities in EF can also contain Complex Properties (in addition to Scalar Properties) and these Complex Properties reference a ComplexType (not a EntityType) DropdownList, ListBox, RadioButtonList, CheckboxList, Bulletedlist are examples of List server controls (not data bound controls) these controls cannot use Complex properties during databinding, they need Scalar Properties. So if a Entity contains Complex properties and you need to bind those to list server controls then use projections to return Scalar properties and bind them to the control (the disadvantage is that projected collections are not tracked by the Object Context and hence cannot persist changes to the projected collections bound to controls) ObjectDataSource and EntityDataSource do account for Complex properties and one can bind entities with Complex Properties to Data Source controls and they will be tracked for changes... with no additional plumbing needed to persist changes to these collections bound to controls So DataBound controls like GridView, FormView need to use EntityDataSource or ObjectDataSource as a datasource for entities that contain Complex properties so that changes to the datasource done using the GridView can be persisted to the DB (enabling the controls for updates)....if you cannot use the EntityDataSource you need to flatten the ComplexType Properties using projections With EF Version 4 ComplexTypes are supported by the Designer and can add/remove/compose Complex Types directly using the Designer =================================================================== Conditional Mapping ... is like Table per Hierarchy Inheritance where Entities inherit from a base class and then used conditions to populate the EntitySet (called conditional Mapping). Conditional Mapping has limitations since you can only use =, is null and IS NOT NULL Conditions to do conditional mapping. If you need more operators for filtering/mapping conditionally then use QueryView(or possibly Defining Query) to create a readonly entity. QueryView are readonly by default... the EntitySet created by the QueryView is enabled for change tracking by the ObjectContext, however the ObjectContext cannot create insert/update/delete TSQL statements for these Entities when SaveChanges is called since it is QueryView. One way to get around this limitation is to map stored procedures for the insert/update/delete operations in the Designer. =================================================================== Difference between QueryView and Defining Query : QueryView is defined in the (MSL) Mapping File/section of the EDM XML, whereas the DefiningQuery is defined in the store schema (SSDL). QueryView is written using Entity SQL and is this database agnostic and can be used against any database/Data Layer. DefiningQuery is written using Database Lanaguage i.e. TSQL or PSQL thus you have more control =================================================================== Performance: Lazy loading is deferred loading done automatically. lazy loading is supported with EF version4 and is on by default. If you need to turn it off then use context.ContextOptions.lazyLoadingEnabled = false To improve Performance consider PreCompiling the ObjectQuery using the CompiledQuery.Compile method

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  • Entity Framework v1 &ndash; tips and Tricks Part 3

    - by Rohit Gupta
    General Tips on Entity Framework v1 & Linq to Entities: ToTraceString() If you need to know the underlying SQL that the EF generates for a Linq To Entities query, then use the ToTraceString() method of the ObjectQuery class. (or use LINQPAD) Note that you need to cast the LINQToEntities query to ObjectQuery before calling TotraceString() as follows: 1: string efSQL = ((ObjectQuery)from c in ctx.Contact 2: where c.Address.Any(a => a.CountryRegion == "US") 3: select c.ContactID).ToTraceString(); ================================================================================ MARS or MultipleActiveResultSet When you create a EDM Model (EDMX file) from the database using Visual Studio, it generates a connection string with the same name as the name of the EntityContainer in CSDL. In the ConnectionString so generated it sets the MultipleActiveResultSet attribute to true by default. So if you are running the following query then it streams multiple readers over the same connection: 1: using (BAEntities context = new BAEntities()) 2: { 3: var cons = 4: from con in context.Contacts 5: where con.FirstName == "Jose" 6: select con; 7: foreach (var c in cons) 8: { 9: if (c.AddDate < new System.DateTime(2007, 1, 1)) 10: { 11: c.Addresses.Load(); 12: } 13: } 14: } ================================================================================= Explicitly opening and closing EntityConnection When you call ToList() or foreach on a LINQToEntities query the EF automatically closes the connection after all the records from the query have been consumed. Thus if you need to run many LINQToEntities queries over the same connection then explicitly open and close the connection as follows: 1: using (BAEntities context = new BAEntities()) 2: { 3: context.Connection.Open(); 4: var cons = from con in context.Contacts where con.FirstName == "Jose" 5: select con; 6: var conList = cons.ToList(); 7: var allCustomers = from con in context.Contacts.OfType<Customer>() 8: select con; 9: var allcustList = allCustomers.ToList(); 10: context.Connection.Close(); 11: } ====================================================================== Dispose ObjectContext only if required After you retrieve entities using the ObjectContext and you are not explicitly disposing the ObjectContext then insure that your code does consume all the records from the LinqToEntities query by calling .ToList() or foreach statement, otherwise the the database connection will remain open and will be closed by the garbage collector when it gets to dispose the ObjectContext. Secondly if you are making updates to the entities retrieved using LinqToEntities then insure that you dont inadverdently dispose of the ObjectContext after the entities are retrieved and before calling .SaveChanges() since you need the SAME ObjectContext to keep track of changes made to the Entities (by using ObjectStateEntry objects). So if you do need to explicitly dispose of the ObjectContext do so only after calling SaveChanges() and only if you dont need to change track the entities retrieved any further. ======================================================================= SQL InjectionAttacks under control with EFv1 LinqToEntities and LinqToSQL queries are parameterized before they are sent to the DB hence they are not vulnerable to SQL Injection attacks. EntitySQL may be slightly vulnerable to attacks since it does not use parameterized queries. However since the EntitySQL demands that the query be valid Entity SQL syntax and valid native SQL syntax at the same time. So the only way one can do a SQLInjection Attack is by knowing the SSDL of the EDM Model and be able to write the correct EntitySQL (note one cannot append regular SQL since then the query wont be a valid EntitySQL syntax) and append it to a parameter. ====================================================================== Improving Performance You can convert the EntitySets and AssociationSets in a EDM Model into precompiled Views using the edmgen utility. for e.g. the Customer Entity can be converted into a precompiled view using edmgen and all LinqToEntities query against the contaxt.Customer EntitySet will use the precompiled View instead of the EntitySet itself (the same being true for relationships (EntityReference & EntityCollections of a Entity)). The advantage being that when using precompiled views the performance will be much better. The syntax for generating precompiled views for a existing EF project is : edmgen /mode:ViewGeneration /inssdl:BAModel.ssdl /incsdl:BAModel.csdl /inmsl:BAModel.msl /p:Chap14.csproj Note that this will only generate precompiled views for EntitySets and Associations and not for existing LinqToEntities queries in the project.(for that use CompiledQuery.Compile<>) Secondly if you have a LinqToEntities query that you need to run multiple times, then one should precompile the query using CompiledQuery.Compile method. The CompiledQuery.Compile<> method accepts a lamda expression as a parameter, which denotes the LinqToEntities query  that you need to precompile. The following is a example of a lamda that we can pass into the CompiledQuery.Compile() method 1: Expression<Func<BAEntities, string, IQueryable<Customer>>> expr = (BAEntities ctx1, string loc) => 2: from c in ctx1.Contacts.OfType<Customer>() 3: where c.Reservations.Any(r => r.Trip.Destination.DestinationName == loc) 4: select c; Then we call the Compile Query as follows: 1: var query = CompiledQuery.Compile<BAEntities, string, IQueryable<Customer>>(expr); 2:  3: using (BAEntities ctx = new BAEntities()) 4: { 5: var loc = "Malta"; 6: IQueryable<Customer> custs = query.Invoke(ctx, loc); 7: var custlist = custs.ToList(); 8: foreach (var item in custlist) 9: { 10: Console.WriteLine(item.FullName); 11: } 12: } Note that if you created a ObjectQuery or a Enitity SQL query instead of the LINQToEntities query, you dont need precompilation for e.g. 1: An Example of EntitySQL query : 2: string esql = "SELECT VALUE c from Contacts AS c where c is of(BAGA.Customer) and c.LastName = 'Gupta'"; 3: ObjectQuery<Customer> custs = CreateQuery<Customer>(esql); 1: An Example of ObjectQuery built using ObjectBuilder methods: 2: from c in Contacts.OfType<Customer>().Where("it.LastName == 'Gupta'") 3: select c This is since the Query plan is cached and thus the performance improves a bit, however since the ObjectQuery or EntitySQL query still needs to materialize the results into Entities hence it will take the same amount of performance hit as with LinqToEntities. However note that not ALL EntitySQL based or QueryBuilder based ObjectQuery plans are cached. So if you are in doubt always create a LinqToEntities compiled query and use that instead ============================================================ GetObjectStateEntry Versus GetObjectByKey We can get to the Entity being referenced by the ObjectStateEntry via its Entity property and there are helper methods in the ObjectStateManager (osm.TryGetObjectStateEntry) to get the ObjectStateEntry for a entity (for which we know the EntityKey). Similarly The ObjectContext has helper methods to get an Entity i.e. TryGetObjectByKey(). TryGetObjectByKey() uses GetObjectStateEntry method under the covers to find the object, however One important difference between these 2 methods is that TryGetObjectByKey queries the database if it is unable to find the object in the context, whereas TryGetObjectStateEntry only looks in the context for existing entries. It will not make a trip to the database ============================================================= POCO objects with EFv1: To create POCO objects that can be used with EFv1. We need to implement 3 key interfaces: IEntityWithKey IEntityWithRelationships IEntityWithChangeTracker Implementing IEntityWithKey is not mandatory, but if you dont then we need to explicitly provide values for the EntityKey for various functions (for e.g. the functions needed to implement IEntityWithChangeTracker and IEntityWithRelationships). Implementation of IEntityWithKey involves exposing a property named EntityKey which returns a EntityKey object. Implementation of IEntityWithChangeTracker involves implementing a method named SetChangeTracker since there can be multiple changetrackers (Object Contexts) existing in memory at the same time. 1: public void SetChangeTracker(IEntityChangeTracker changeTracker) 2: { 3: _changeTracker = changeTracker; 4: } Additionally each property in the POCO object needs to notify the changetracker (objContext) that it is updating itself by calling the EntityMemberChanged and EntityMemberChanging methods on the changeTracker. for e.g.: 1: public EntityKey EntityKey 2: { 3: get { return _entityKey; } 4: set 5: { 6: if (_changeTracker != null) 7: { 8: _changeTracker.EntityMemberChanging("EntityKey"); 9: _entityKey = value; 10: _changeTracker.EntityMemberChanged("EntityKey"); 11: } 12: else 13: _entityKey = value; 14: } 15: } 16: ===================== Custom Property ==================================== 17:  18: [EdmScalarPropertyAttribute(IsNullable = false)] 19: public System.DateTime OrderDate 20: { 21: get { return _orderDate; } 22: set 23: { 24: if (_changeTracker != null) 25: { 26: _changeTracker.EntityMemberChanging("OrderDate"); 27: _orderDate = value; 28: _changeTracker.EntityMemberChanged("OrderDate"); 29: } 30: else 31: _orderDate = value; 32: } 33: } Finally you also need to create the EntityState property as follows: 1: public EntityState EntityState 2: { 3: get { return _changeTracker.EntityState; } 4: } The IEntityWithRelationships involves creating a property that returns RelationshipManager object: 1: public RelationshipManager RelationshipManager 2: { 3: get 4: { 5: if (_relManager == null) 6: _relManager = RelationshipManager.Create(this); 7: return _relManager; 8: } 9: } ============================================================ Tip : ProviderManifestToken – change EDMX File to use SQL 2008 instead of SQL 2005 To use with SQL Server 2008, edit the EDMX file (the raw XML) changing the ProviderManifestToken in the SSDL attributes from "2005" to "2008" ============================================================= With EFv1 we cannot use Structs to replace a anonymous Type while doing projections in a LINQ to Entities query. While the same is supported with LINQToSQL, it is not with LinqToEntities. For e.g. the following is not supported with LinqToEntities since only parameterless constructors and initializers are supported in LINQ to Entities. (the same works with LINQToSQL) 1: public struct CompanyInfo 2: { 3: public int ID { get; set; } 4: public string Name { get; set; } 5: } 6: var companies = (from c in dc.Companies 7: where c.CompanyIcon == null 8: select new CompanyInfo { Name = c.CompanyName, ID = c.CompanyId }).ToList(); ;

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  • When trying to install Wine on 12.10, 'Sudo' command will not let me type in a password.

    - by Nocturnus
    As the title explains, I have been attempting to install Wine on my laptop which is running 12.10. When I access the command terminal and entered "sudo add-apt-repository ppa:ubuntu-wine/ppa" I was of course met by a password block, when I attempted to enter my password, it flat out wouldn't let me type anything, the only key that got a response from the terminal was "enter" which was met by "incorrect password". To bypass this issue I backed out and used the 'Gksudo' command, this new dialogue box seemed to give me access to sudo commands. I then entered "sudo apt-get update" and "sudo apt-get install wine1.5". Up until the installation everything went fine, but after entering the final command (still using gksudo) The terminal read "the following packages have unmet dependencies" and proceeded to list a bunch of "recommends" So my guess is that Wine hasn't been updated to run on 12.10... Is this true, and is there any other way to open .exe's? Also what was with that funky password misshap? I'm totally new to Ubuntu so I've just been using support pages and tutorials, sorry if I'm a bit naive in these matters...

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  • Complex Rails queries across multiple tables, unions, and will_paginate. Solved.

    - by uberllama
    Hi folks. I've been working on a complex "user feed" type of functionality for a while now, and after experimenting with various union plugins, hacking named scopes, and brute force, have arrived at a solution I'm happy with. S.O. has been hugely helpful for me, so I thought I'd post it here in hopes that it might help others and also to get feedback -- it's very possible that I worked on this so long that I walked down an unnecessarily complicated road. For the sake of my example, I'll use users, groups, and articles. A user can follow other users to get a feed of their articles. They can also join groups and get a feed of articles that have been added to those groups. What I needed was a combined, pageable feed of distinct articles from a user's contacts and groups. Let's begin. user.rb has_many :articles has_many :contacts has_many :contacted_users, :through => :contacts has_many :memberships has_many :groups, :through => :memberships contact.rb belongs_to :user belongs_to :contacted_user, :class_name => "User", :foreign_key => "contacted_user_id" article.rb belongs_to :user has_many :submissions has_many :groups, :through => :submissions group.rb has_many :memberships has_many :users, :through => :memberships has_many :submissions has_many :articles, :through => :submissions Those are the basic models that define my relationships. Now, I add two named scopes to the Article model so that I can get separate feeds of both contact articles and group articles should I desire. article.rb # Get all articles by user's contacts named_scope :by_contacts, lambda {|user| {:joins => "inner join contacts on articles.user_id = contacts.contacted_user_id", :conditions => ["articles.published = 1 and contacts.user_id = ?", user.id]} } # Get all articles in user's groups. This does an additional query to get the user's group IDs, then uses those in an IN clause named_scope :by_groups, lambda {|user| {:select => "DISTINCT articles.*", :joins => :submissions, :conditions => {:submissions => {:group_id => user.group_ids}}} } Now I have to create a method that will provide a UNION of these two feeds into one. Since I'm using Rails 2.3.5, I have to use the construct_finder_sql method to render a scope into its base sql. In Rails 3.0, I could use the to_sql method. user.rb def feed "(#{Article.by_groups(self).send(:construct_finder_sql,{})}) UNION (#{Article.by_contacts(self).send(:construct_finder_sql,{})})" end And finally, I can now call this method and paginate it from my controller using will_paginate's paginate_by_sql method. HomeController.rb @articles = Article.paginate_by_sql(current_user.feed, :page => 1) And we're done! It may seem simple now, but it was a lot of work getting there. Feedback is always appreciated. In particular, it would be great to get away from some of the raw sql hacking. Cheers.

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  • Exclamation Marks in a Query SQL

    - by mikeabyss
    I'm reading over this query, and I came upon a line where I don't understand heres the line [FETT List]![FETT Search] FETT List is a table And FETT Search is a column in FETT List Can someone explain what the exclamation mark means? Thanks

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