Search Results

Search found 47408 results on 1897 pages for 'database machine'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 379/1897 | < Previous Page | 375 376 377 378 379 380 381 382 383 384 385 386  | Next Page >

  • querying larg text file containing JSON objects.

    - by Maciek Sawicki
    Hi, I have few Gigabytes text file in format: {"user_ip":"x.x.x.x", "action_type":"xxx", "action_data":{"some_key":"some_value"...},...} each entry is one line. First I would like to easily find entries for given ip. This part is easy because I can use grep for example. However even for this I would like to find better solution because I would like to get response as fast as possible. Next part is more complicated because I would like to find entries from selected ip and of selected type and with particular value of some_key in action_data. Probably I would have to convert this file to SQL db (probably SQLite, because it will be desktop APP), but I would ask if there are exists better solutions?

    Read the article

  • Deploying and hosting scala in the cloud?

    - by TiansHUo
    I am starting a web app considering scalability as one of the top priorities. What would be the benefits of this: cassandra scala lift vs the traditional LAMP on the cloud? Since from what I've read, please correct me, the cloud itself is scalable I have never seen anyone deploy scala on the cloud before. Is it worth the effort to learn the platform? Is it ready for production use?

    Read the article

  • T-SQL MERGE - finding out which action it took

    - by IanC
    I need to know if a MERGE statement performed an INSERT. In my scenario, the insert is either 0 or 1 rows. Test code: DECLARE @t table (C1 int, C2 int) DECLARE @C1 INT, @C2 INT set @c1 = 1 set @c2 = 1 MERGE @t as tgt USING (SELECT @C1, @C2) AS src (C1, C2) ON (tgt.C1 = src.C1) WHEN MATCHED AND tgt.C2 != src.C2 THEN UPDATE SET tgt.C2 = src.C2 WHEN NOT MATCHED BY TARGET THEN INSERT VALUES (src.C1, src. C2) OUTPUT deleted.*, $action, inserted.*; SELECT inserted.* The last line doesn't compile (no scope, unlike a trigger). I can't get access to @action, or the output. Actually, I don't want any output meta data. How can I do this?

    Read the article

  • Using NULLs in matchup table

    - by TomWilsonFL
    I am working on the accounting portion of a reservation system (think limo company). In the system there are multiple objects that can either be paid or submit a payment. I am tracking all of these "transactions" in three tables called: tx, tx_cc, and tx_ch. tx generates a new tx_id (for transaction ID) and keeps the information about amount, validity, etc. Tx_cc and tx_ch keep the information about the credit card or check used, respectively, which link to other tables (credit_card and bank_account among others). This seems fairly normalized to me, no? Now here is my problem: The payment transaction can take place for a myriad of reasons. Either a reservation is being paid for, a travel agent that booked a reservation is being paid, a driver is being paid, etc. This results in multiple tables, one for each of the entities: agent_tx, driver_tx, reservation_tx, etc. They look like this: CREATE TABLE IF NOT EXISTS `driver_tx` ( `tx_id` int(10) unsigned zerofill NOT NULL, `driver_id` int(11) NOT NULL, `reservation_id` int(11) default NULL, `reservation_item_id` int(11) default NULL, PRIMARY KEY (`tx_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; Now this transaction is for a driver, but could be applied to an individual item on the reservation or the entire reservation overall. Therefore I demand either reservation_id OR reservation_item_id to be null. In the future there may be other things which a driver is paid for, which I would also add to this table, defaulting to null. What is the rule on this? Opinion? Obviously I could break this out into MANY three column tables, but the amount of OUTER JOINing needed seems outrageous. Your input is appreciated. Peace, Tom

    Read the article

  • Migrating from hand-written persistence layer to ORM

    - by Sergey Mikhanov
    Hi community, We are currently evaluating options for migrating from hand-written persistence layer to ORM. We have a bunch of legacy persistent objects (~200), that implement simple interface like this: interface JDBC { public long getId(); public void setId(long id); public void retrieve(); public void setDataSource(DataSource ds); } When retrieve() is called, object populates itself by issuing handwritten SQL queries to the connection provided using the ID it received in the setter (this usually is the only parameter to the query). It manages its statements, result sets, etc itself. Some of the objects have special flavors of retrive() method, like retrieveByName(), in this case a different SQL is issued. Queries could be quite complex, we often join several tables to populate the sets representing relations to other objects, sometimes join queries are issued on-demand in the specific getter (lazy loading). So basically, we have implemented most of the ORM's functionality manually. The reason for that was performance. We have very strong requirements for speed, and back in 2005 (when this code was written) performance tests has shown that none of mainstream ORMs were that fast as hand-written SQL. The problems we are facing now that make us think of ORM are: Most of the paths in this code are well-tested and are stable. However, some rarely-used code is prone to result set and connection leaks that are very hard to detect We are currently squeezing some additional performance by adding caching to our persistence layer and it's a huge pain to maintain the cached objects manually in this setup Support of this code when DB schema changes is a big problem. I am looking for an advice on what could be the best alternative for us. As far as I know, ORMs has advanced in last 5 years, so it might be that now there's one that offers an acceptable performance. As I see this issue, we need to address those points: Find some way to reuse at least some of the written SQL to express mappings Have the possibility to issue native SQL queries without the necessity to manually decompose their results (i.e. avoid manual rs.getInt(42) as they are very sensitive to schema changes) Add a non-intrusive caching layer Keep the performance figures. Is there any ORM framework you could recommend with regards to that?

    Read the article

  • how to model a follower stream in appengine?

    - by molicule
    I am trying to design tables to buildout a follower relationship. Say I have a stream of 140char records that have user, hashtag and other text. Users follow other users, and can also follow hashtags. I am outlining the way I've designed this below, but there are two limitaions in my design. I was wondering if others had smarter ways to accomplish the same goal. The issues with this are The list of followers is copied in for each record If a new follower is added or one removed, 'all' the records have to be updated. The code class HashtagFollowers(db.Model): """ This table contains the followers for each hashtag """ hashtag = db.StringProperty() followers = db.StringListProperty() class UserFollowers(db.Model): """ This table contains the followers for each user """ username = db.StringProperty() followers = db.StringListProperty() class stream(db.Model): """ This table contains the data stream """ username = db.StringProperty() hashtag = db.StringProperty() text = db.TextProperty() def save(self): """ On each save all the followers for each hashtag and user are added into a another table with this record as the parent """ super(stream, self).save() hfs = HashtagFollowers.all().filter("hashtag =", self.hashtag).fetch(10) for hf in hfs: sh = streamHashtags(parent=self, followers=hf.followers) sh.save() ufs = UserFollowers.all().filter("username =", self.username).fetch(10) for uf in ufs: uh = streamUsers(parent=self, followers=uf.followers) uh.save() class streamHashtags(db.Model): """ The stream record is the parent of this record """ followers = db.StringListProperty() class streamUsers(db.Model): """ The stream record is the parent of this record """ followers = db.StringListProperty() Now, to get the stream of followed hastags indexes = db.GqlQuery("""SELECT __key__ from streamHashtags where followers = 'myusername'""") keys = [k,parent() for k in indexes[offset:numresults]] return db.get(keys) Is there a smarter way to do this?

    Read the article

  • Question about joins and table with Millions of rows

    - by xRobot
    I have to create 2 tables: Magazine ( 10 millions of rows with these columns: id, title, genres, printing, price ) Author ( 180 millions of rows with these columns: id, name, magazine_id ) . Every author can write on ONLY ONE magazine and every magazine has more authors. So if I want to know all authors of Motors Magazine, I have to use this query: SELECT * FROM Author, Magazine WHERE ( Author.id = Magazine.id ) AND ( genres = 'Motors' ) The same applies to Printing and Price column. To avoid these joins with tables of millions of rows, I thought to use this tables: Magazine ( 10 millions of rows with this column: id, title, genres, printing, price ) Author ( 180 millions of rows with this column: id, name, magazine_id, genres, printing, price ) . and this query: SELECT * FROM Author WHERE genres = 'Motors' Is it a good approach ? I can use Postgresql or Mysql.

    Read the article

  • SQL Server Concatinate string column value to 5 char long

    - by mrp
    Scenario: I have a table1(col1 char(5)); A value in table1 may '001' or '01' or '1'. Requirement: Whatever value in col1, I need to retrive it in 5 char length concatenate with leading '0' to make it 5 char long. Technique I applied: select right(('00000' + col1),5) from table1; I didn't see any reason, why it doesn't work? but it didn't. Can anyone help me, how I can achieve the desired result?

    Read the article

  • Creating an appropriate index for a frequently used query in SQL Server

    - by Slauma
    In my application I have two queries which will be quite frequently used. The Where clauses of these queries are the following: WHERE FieldA = @P1 AND (FieldB = @P2 OR FieldC = @P2) and WHERE FieldA = @P1 AND FieldB = @P2 P1 and P2 are parameters entered in the UI or coming from external datasources. FieldA is an int and highly on-unique, means: only two, three, four different values in a table with say 20000 rows FieldB is a varchar(20) and is "almost" unique, there will be only very few rows where FieldB might have the same value FieldC is a varchar(15) and also highly distinct, but not as much as FieldB FieldA and FieldB together are unique (but do not form my primary key, which is a simple auto-incrementing identity column with a clustered index) I'm wondering now what's the best way to define an index to speed up specifically these two queries. Shall I define one index with... FieldB (or better FieldC here?) FieldC (or better FieldB here?) FieldA ... or better two indices: FieldB FieldA and FieldC FieldA Or are there even other and better options? What's the best way and why? Thank you for suggestions in advance!

    Read the article

  • How Can I prevent a specific application from being run on a specific machine using Group Policy?

    - by Mike
    I know this is possible to do and I am working on it with limited success. I believe the Group Policy I want is "Do Not Run Specified Windows Applications" - I can enable this and add the .exe I want to the list of programs not to be run. I have tried this on my local machine by running gpedit.msc going to User Config Admin Templates System and then choosing that policy and editing and enabling it. Doing it this way verifies that it works as I could then not run the specified .exe (XenAppWeb.exe) So this is great. I have created a GPO to do the same thing in GP Management on my domain controller where we centralize this, enforced it, applied it to an OU, and put one of our machines into this OU to test it. I have let it sit there for 3 days, run gpupdate /force, and when I try to run XenAppWeb.exe on this machine, it still lets me run it fine. What can I look at to troubleshoot this? I should note that I am trying to enact this policy on Windows XP machines (Virtual Machines) Thanks, Mike

    Read the article

  • mysql subquery strangely slow

    - by aviv
    I have a query to select from another sub-query select. While the two queries look almost the same the second query (in this sample) runs much slower: SELECT user.id ,user.first_name -- user.* FROM user WHERE user.id IN (SELECT ref_id FROM education WHERE ref_type='user' AND education.institute_id='58' AND education.institute_type='1' ); This query takes 1.2s Explain on this query results: id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY user index first_name 152 141192 Using where; Using index 2 DEPENDENT SUBQUERY education index_subquery ref_type,ref_id,institute_id,institute_type,ref_type_2 ref_id 4 func 1 Using where The second query: SELECT -- user.id -- user.first_name user.* FROM user WHERE user.id IN (SELECT ref_id FROM education WHERE ref_type='user' AND education.institute_id='58' AND education.institute_type='1' ); Takes 45sec to run, with explain: id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY user ALL 141192 Using where 2 DEPENDENT SUBQUERY education index_subquery ref_type,ref_id,institute_id,institute_type,ref_type_2 ref_id 4 func 1 Using where Why is it slower if i query only by index fields? Why both queries scans the full length of the user table? Any ideas how to improve? Thanks.

    Read the article

  • MySQL Table structure of thumb UP & DOWN for comments system ?

    - by Axel
    Hello, i already created a table for comments but i want to add the feature of thumb Up and Down for comments like Digg and Youtube, i use php & mysql and i'm wondering What's the best table scheme to implement that so comments with many likes will be on the top. This is my current comments table : comments(id,user,article,comment,stamp) Note: Only registred will be able to vote, so there isn't need to restrict the votes by IP Thanks

    Read the article

  • Desimal data Type Display scale part as zero

    - by Wael Dalloul
    I have Decimal field in SQLserver 2005 table, Price decimal(18, 4) if I write 12 it will be converted to 12.0000, if I write 12.33 it will be converted into 12.3300. Always it's putting zero to the right of the decimal point in the count of Scale Part(4). I was using these in SQL Server 2000, it was not behaving like this, in SQL Server 2000 if I put 12.5 it will be stored as 12.5 not as 12.5000 what SQLServer2005 do. My Question is how to stop SQL Server 2005 from putting zeros to the right of the decimal point?

    Read the article

  • In SQL server, to convert a varchar which have this format (nnn:nn:nn)

    - by user1688917
    I have this varchar format as time accumulation and i want to convert it to an integer to do a SUM and get the total time for a group. The fist part which may be 1, 2, 3, 4 or even five digits represent the accumulation of Hours and then seperated by a colon. then come the second part which is accumulation of minutes and last accumulation of seconds (2 digits each). How to convert this to integer in one query if possile.

    Read the article

  • Self-relation messes up contents in fetching

    - by holographix
    Hi folks, I'm dealing with an annoying problem in core data I've got a table named Character, which is made as follows I'm filling the table in various steps: 1) fill the attributes of the table 2) fill the Character Relation (charRel) FYI charRel is defined as follows I'm feeding the contents by pulling the data from an xml, the feeding code is this curStr = [[NSMutableString stringWithString:[curStr stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]] retain]; NSLog(@"Parsing relation within these keys %@, in order to get'em associated",curStr); NSArray *chunks = [curStr componentsSeparatedByString: @","]; for( NSString *relId in chunks ) { NSLog(@"Associating %@ with id %@",[currentCharacter valueForKey:@"character_id"], relId); NSFetchRequest *request = [[NSFetchRequest alloc] init]; NSPredicate *predicate = [NSPredicate predicateWithFormat:@"character_id == %@", relId]; [request setEntity:[NSEntityDescription entityForName:@"Character" inManagedObjectContext:[self managedObjectContext] ]]; [request setPredicate:predicate]; NSerror *error = nil; NSArray *results = [[self managedObjectContext] executeFetchRequest:request error:&error]; // error handling code if(error != nil) { NSLog(@"[SYMBOL CORRELATION]: retrieving correlated symbol error: %@", [error localizedDescription]); } else if([results count] > 0) { Character *relatedChar = [results objectAtIndex:0]; // grab the first result in the stack, could be done better! [currentCharacter addCharRelObject:relatedChar]; //VICE VERSA RELATIONS NSArray *charRels = [relatedChar valueForKey:@"charRel"]; BOOL alreadyRelated = NO; for(Character *charRel in charRels) { if([[charRel valueForKey:@"character_id"] isEqual:[currentCharacter valueForKey:@"character_id"]]) { alreadyRelated = YES; break; } } if(!alreadyRelated) { NSLog(@"\n\t\trelating %@ with %@", [relatedChar valueForKey:@"character_id"], [currentCharacter valueForKey:@"character_id"]); [relatedChar addCharRelObject:currentCharacter]; } } else { NSLog(@"[SYMBOL CORRELATION]: related symbol was not found! ##SKIPPING-->"); } [request release]; } NSLog(@"\t\t### TOTAL OF REALTIONS FOR ID %@: %d\n%@", [currentCharacter valueForKey:@"character_id"], [[currentCharacter valueForKey:@"charRel"] count], currentCharacter); error = nil; /* SAVE THE CONTEXT */ if (![managedObjectContext save:&error]) { NSLog(@"Whoops, couldn't save the symbol record: %@", [error localizedDescription]); NSArray* detailedErrors = [[error userInfo] objectForKey:NSDetailedErrorsKey]; if(detailedErrors != nil && [detailedErrors count] > 0) { for(NSError* detailedError in detailedErrors) { NSLog(@"\n################\t\tDetailedError: %@\n################", [detailedError userInfo]); } } else { NSLog(@" %@", [error userInfo]); } } at this point when I print out the values of the currentCharacter, everything looks perfect. every relation is in its place. in example in this log we can clearly see that this element has got 3 items in charRel: <Character: 0x5593af0> (entity: Character; id: 0x55938c0 <x-coredata://67288D50-D349-4B19-B7CB-F7AC4671AD61/Character/p86> ; data: { catRel = "<relationship fault: 0x9a29db0 'catRel'>"; charRel = ( "0x9a1f870 <x-coredata://67288D50-D349-4B19-B7CB-F7AC4671AD61/Character/p74>", "0x9a14bd0 <x-coredata://67288D50-D349-4B19-B7CB-F7AC4671AD61/Character/p109>", "0x558ba00 <x-coredata://67288D50-D349-4B19-B7CB-F7AC4671AD61/Character/p5>" ); "character_id" = 254; examplesRel = "<relationship fault: 0x9a29df0 'examplesRel'>"; meaning = "\n Left"; pinyin = "\n zu\U01d2"; "pronunciation_it" = "\n zu\U01d2"; strokenumber = 5; text = "\n \n <p>The most ancient form of this symbol"; unicodevalue = "\n \U5de6"; }) then when I'm in need of retrieving this item I perform an extraction, like this: // at first I get the single Character record NSFetchRequest *request = [[NSFetchRequest alloc] init]; NSError *error; NSPredicate *predicate = [NSPredicate predicateWithFormat:@"character_id == %@", self.char_id ]; [request setEntity:[NSEntityDescription entityForName:@"Character" inManagedObjectContext:_context ]]; [request setPredicate:predicate]; NSArray *fetchedObjs = [_context executeFetchRequest:request error:&error]; when, for instance, I print out in NSLog the contents of charRel NSArray *correlations = [singleCharacter valueForKey:@"charRel"]; NSLog(@"CHARACTER OBJECT \n%@", correlations); I get this Relationship fault for (<NSRelationshipDescription: 0x5568520>), name charRel, isOptional 1, isTransient 0, entity Character, renamingIdentifier charRel, validation predicates (), warnings (), versionHashModifier (null), destination entity Character, inverseRelationship (null), minCount 1, maxCount 99 on 0x6937f00 hope that I made myself clear. this thing is driving me insane, I've googled all over world, but I couldn't find a solution (and this make me think to as issue related to bad coding somehow :P). thank you in advance guys. k

    Read the article

  • What is the most efficient procedure for implementing a sortable ajax list on the backend?

    - by HenryL
    The most common method is to assign a sequential order field for each item in the list and do an update that maintains the sequence with every ajax sort operation. Unfortunately, this requires an update to each item of the list every time someone sorts. This is fine for small lists, but what's the best way to implement sorting for larger lists that are constantly updated? I am looking for something that minimizes DB IO.

    Read the article

  • Update query with conditional?

    - by dmontain
    I'm not sure if this possible. If not, let me know. I have a PDO mysql that updates 3 fields. $update = $mypdo->prepare("UPDATE tablename SET field1=:field1, field2=:field2, field3=:field3 WHERE key=:key"); But I want field3 to be updated only when $update3 = true; (meaning that the update of field3 is controlled by a conditional statement) Is this possible to accomplish with a single query? I could do it with 2 queries where I update field1 and field2 then check the boolean and update field3 if needed in a separate query. //run this query to update only fields 1 and 2 $update_part1 = $mypdo->prepare("UPDATE tablename SET field1=:field1, field2=:field2 WHERE key=:key"); //if field3 should be update, run a separate query to update it separately if ($update3){ $update_part2 = $mypdo->prepare("UPDATE tablename SET field3=:field3 WHERE key=:key"); } But hopefully there is a way to accomplish this in 1 query?

    Read the article

  • How to figure out which record has been deleted in an effiecient way?

    - by janetsmith
    Hi, I am working on an in-house ETL solution, from db1 (Oracle) to db2 (Sybase). We needs to transfer data incrementally (Change Data Capture?) into db2. I have only read access to tables, so I can't create any table or trigger in Oracle db1. The challenge I am facing is, how to detect record deletion in Oracle? The solution which I can think of, is by using additional standalone/embedded db (e.g. derby, h2 etc). This db contains 2 tables, namely old_data, new_data. old_data contains primary key field from tahle of interest in Oracle. Every time ETL process runs, new_data table will be populated with primary key field from Oracle table. After that, I will run the following sql command to get the deleted rows: SELECT old_data.id FROM old_data WHERE old_data.id NOT IN (SELECT new_data.id FROM new_data) I think this will be a very expensive operation when the volume of data become very large. Do you have any better idea of doing this? Thanks.

    Read the article

  • How do I perform 'WHERE' on groups of rows?

    - by Drew
    I have a table, which looks like: +-----------+----------+ + person_id + group_id + +-----------+----------+ + 1 + 10 + + 1 + 20 + + 1 + 30 + + 2 + 10 + + 2 + 20 + + 3 + 10 + +-----------+----------+ I need a query such that only person_ids with groups 10 AND 20 AND 30 are returned (only person_id: 1). I am not sure how to do this, as from what I can see it would require me to group the rows by person_id and then select the rows which contain all group_ids. I'm looking for something which will preserve the use of keys without resorting to string operations on group_concat() or such.

    Read the article

  • What is the corrrect way to increment a field making up part of a composit key

    - by Tr1stan
    I have a bunch of tables whose primary key is made up of the foreign keys of other tables (Composite key). Therefore for example the attributes (as a very cut down version) might look like this: A[aPK, SomeFields] 1:M B[bPK, aFK, SomeFields] 1:M C[cPK, bFK, aFK, SomeFields] as data this could look like: A[aPK, SomeFields]: 1, Foo 2, Bar B[bPK, aFK, SomeFields]: 1, 1, FooData1 2, 1, FooData2 1, 2, BarData1 2, 2, BarData2 C[cPK, bFK, aFK, SomeFields]: 1, 1, 1, FooData1More 2, 1, 1, FooData1More 1, 2, 1, FooData2More 2, 2, 1, FooData2More 1, 1, 2, BarData1More 2, 1, 2, BarData1More 1, 2, 2, BarData2More 2, 2, 2, BarData2More I've got this running in a MSSQL DBMS and I'm looking for the best way to increment the left most column, in each table when a new tuple is added to it. I can't use the Auto Increment Identity Specification option as that has no idea that it is part of a composite key. I also don't want to use any aggregate function such as: MAX(field)+1 as this will have adverse affects with multiple users inputting data, rolling back etc. There might however be a nice trigger based option here, but I'm not sure. This must be a common issue so I'm hoping that someone has a lovely solution. As a side which may or may not affect the answer, I'm using Entity Framework 1.0 as my ORM, within a c# MVC application.

    Read the article

  • Two radically different queries against 4 mil records execute in the same time - one uses brute force.

    - by IanC
    I'm using SQL Server 2008. I have a table with over 3 million records, which is related to another table with a million records. I have spent a few days experimenting with different ways of querying these tables. I have it down to two radically different queries, both of which take 6s to execute on my laptop. The first query uses a brute force method of evaluating possibly likely matches, and removes incorrect matches via aggregate summation calculations. The second gets all possibly likely matches, then removes incorrect matches via an EXCEPT query that uses two dedicated indexes to find the low and high mismatches. Logically, one would expect the brute force to be slow and the indexes one to be fast. Not so. And I have experimented heavily with indexes until I got the best speed. Further, the brute force query doesn't require as many indexes, which means that technically it would yield better overall system performance. Below are the two execution plans. If you can't see them, please let me know and I'll re-post then in landscape orientation / mail them to you. Brute-force query: Index-based exception query: My question is, based on the execution plans, which one look more efficient? I realize that thing may change as my data grows.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 375 376 377 378 379 380 381 382 383 384 385 386  | Next Page >