Search Results

Search found 33585 results on 1344 pages for 'sql execution plan'.

Page 626/1344 | < Previous Page | 622 623 624 625 626 627 628 629 630 631 632 633  | Next Page >

  • Why connection in Python's DB-API does not have "begin" operation?

    - by newtover
    Working with cursors in mysql-python I used to call "BEGIN;", "COMMIT;", and "ROLLBACK;" explicitly as follows: try: cursor.execute("BEGIN;") # some statements cursor.execute("COMMIT;") except: cursor.execute("ROLLBACK;") then, I found out that the underlying connection object has the corresponding methods: try: cursor.connection.begin() # some statements cursor.connection.commit() except: cursor.connection.rollback() Inspecting the DB-API PEP I found out that it does not mention the begin() method for the connection object, even for the extensions. Mysql-python, by the way, throws the Deprecation Warning, when you use the method. sqlite3.connection, for example, does not have the methd at all. And the question is why there is no such method in the PEP? Is the statement somehow optional, is it enough to invoke commit() instead?

    Read the article

  • Ruby on rails active-record generated SQL on Postgres

    - by jpartogi
    Dear all, Why does Ruby on rails generated more queries in the background on Postgres than MySQL? I haven't tried deploying Rails on production with Postgres yet, but I am just afraid this generated queries would affect the performance. Do you find Rails with Postgres is slower than MySQL, knowing that it produce more query on the background? Or it is relatively the same?

    Read the article

  • sql query - how to apply limit within group by

    - by Raj
    hey guys assuming i have a table named t1 with following fields: ROWID, CID, PID, Score, SortKey it has the following data: 1, C1, P1, 10, 1 2, C1, P2, 20, 2 3, C1, P3, 30, 3 4, C2, P4, 20, 3 5, C2, P5, 30, 2 6, C3, P6, 10, 1 7, C3, P7, 20, 2 what query do i write so that it applies group by on CID, but instead of returning me 1 single result per group, it returns me a max of 2 results per group. also where condition is score = 20 and i want the results ordered by CID and SortKey. If I had to run my query on above data, i would expect the following result: RESULTS FOR C1 - note: ROWID 1 is not considered as its score < 20 C1, P2, 20, 2 C1, P3, 30, 3 RESULTS FOR C2 - note: ROWID 5 appears before ROWID 4 as ROWID 5 has lesser value SortKey C2, P5, 30, 2 C2, P4, 20, 3 RESULTS FOR C3 - note: ROWID 6 does not appear as its score is less than 20 so only 1 record returned here C3, P7, 20, 2 IN SHORT, I WANT A LIMIT WITHIN A GROUP BY. I want the simplest solution and want to avoid temp tables. sub queries are fine. also note i am using sqlite for this

    Read the article

  • How to get distinct values from a column with all its corresponding values in another column

    - by Vishnu
    I know the question is bit confusing. Please read below. I have a table table_categories (id INT(11), cname VARCHAR(25),survey_id INT(11)) I want to retrieve the values for the column cname without duplication, that is distinct values but with all the values in the other column. id cname survey_id -- -------- --------- 1 Trader 2 2 Beginner 2 25 Human 1 26 Human 2 From the above example I want to retrieve distinct cnames with all the values of the survey_id. I don't want to use any programming language. Is there any way by using a single query. Please give me a solution in MySQL.

    Read the article

  • Building a subquery with ARel in Rails3

    - by Christopher
    I am trying to build this query in ARel: SELECT FLOOR(AVG(num)) FROM ( SELECT COUNT(attendees.id) AS num, meetings.club_id FROM `meetings` INNER JOIN `attendees` ON `attendees`.`meeting_id` = `meetings`.`id` WHERE (`meetings`.club_id = 1) GROUP BY meetings.id) tmp GROUP BY tmp.club_id It returns the average number of attendees per meeting, per club. (a club has many meetings and a meeting has many attendees) So far I have (declared in class Club < ActiveRecord::Base): num_attendees = meetings.select("COUNT(attendees.id) AS num").joins(:attendees).group('meetings.id') Arel::Table.new('tmp', self.class.arel_engine).from(num_attendees).project('FLOOR(AVG(num))').group('tmp.club_id').to_sql but, I am getting the error: undefined method `visit_ActiveRecord_Relation' for #<Arel::Visitors::MySQL:0x9b42180> The documentation for generating non trivial ARel queries is a bit hard to come by. I have been using http://rdoc.info/github/rails/arel/master/frames Am I approaching this incorrectly? Or am I a few methods away from a solution?

    Read the article

  • How do I save an object that contains and EntitySet?

    - by Pete
    Say I have an User (mapped to a User table) and the Edit view (in MVC) displays a multiselectlist of Modules (mapped to a Modules table) that user can access, with the Modules pre-selected based on the User's EntitySet of Modules. I have tried saving the User then deleting all User_Modules manually and adding them back based on what's selected on submit, but the User has a null EntitySet for User.User_Modules. I cannot find the correct way to handle this scenario anywhere online. Can anyone help?

    Read the article

  • Is the RESTORE process dependent on schema?

    - by Martin Aatmaa
    Let's say I have two database instances: InstanceA - Production server InstanceB - Test server My workflow is to deploy new schema changes to InstanceB first, test them, and then deploy them to InstanceA. So, at any one time, the instance schema relationship looks like this: InstanceA - Schema Version 1.5 InstanceB - Schema Version 1.6 (new version being tested) An additional part of my workflow is to keep the data in InstanceB as fresh as possible. To fulfill this, I am taking the database backups of InstanceA and applying them (restoring them) to InstanceB. My question is, how does schema version affect the restoral process? I know I can do this: Backup InstanceA - Schema Version 1.5 Restore to InstanceB - Schema Version 1.5 But can I do this? Backup InstanceA - Schema Version 1.5 Restore to InstanceB - Schema Version 1.6 (new version being tested) If no, what would the failure look like? If yes, would the type of schema change matter? For example, if Schema Version 1.6 differed from Schema Version 1.5 by just having an altered storec proc, I imagine that this type of schema change should't affect the restoral process. On the other hand, if Schema Version 1.6 differed from Schema Version 1.5 by having a different table definition (say, an additional column), I image this would affect the restoral process. I hope I've made this clear enough. Thanks in advance for any input!

    Read the article

  • Complex LINQ paging algorithm

    - by sharepointmonkey
    We have a list of projects that may or may not have a collection of subprojects. Our report needs to contain all the projects except those that are the parent project of a subproject. I need to page this into pages of, say, 25 rows. But if subprojects appear on that page then ALL the subprojects of that project must appear on the same page. So more than 25 items may appear if necessary. I've got as far as var pagedProjects = db.Projects.Where(x => !x.SubProjects.Any()).Skip( (pageNo -1) * pageSize).Take(pageSize); Obviously, this fails the second part of the requirements. As a further pain in the arse, I need to have a pager control on the report. So I'll need to be able to calculate the total number of pages. I could loop through the whole table of projects but the performance will suffer. Can anybody come up with a paged solution? EDIT - I should probably mention that SubProjects joins back onto Projects via a selfreferencing foreign key so the whole lot comes back as an IQueryable<Project>.

    Read the article

  • Query a range of date

    - by juniorSE
    Hello Guys, Im trying to query a sort of from - to date. e.g. 20-01-2010 to 20-02-2010. this should include the mentioned dates. i've tried the following queries but none works. select * from [tableName] where date = '20-01-2010' AND date <= '20-02-2010' the date where date is equal to 20-02-2010 does not show. i don't know why. select * from [tableName] where date between '20-01-2010' AND '20-02-2010' the mentioned dates is not included in the results. i want it to be included in the results. please help. thanks in advance! :)

    Read the article

  • Spaced repetition (SRS) for learning

    - by Fredrik Johansson
    A client has asked me to add a simple spaced repeition algorithm (SRS) for an onlinebased learning site. But before throwing my self into it, I'd like to discuss it with the community. Basically the site asks the user a bunch of questions (by automatically selecting say 10 out of 100 total questions from a database), and the user gives either a correct or incorrect answer. The users result are then stored in a database, for instance: userid questionid correctlyanswered dateanswered 1 123 0 (no) 2010-01-01 10:00 1 124 1 (yes) 2010-01-01 11:00 1 125 1 (yes) 2010-01-01 12:00 Now, to maximize a users ability to learn all answers, I should be able to apply an SRS algorithm so that a user, next time he takes the quiz, receives questions incorrectly answered more often; than questions answered correctly. Also, questions that are previously answered incorrectly, but recently often answered correctly should occur less often. Have anyone implemented something like this before? Any tips or suggestions? Theese are the best links I've found: http://en.wikipedia.org/wiki/Spaced_repetition http://www.mnemosyne-proj.org/principles.php http://www.supermemo.com/english/ol/sm2.htm

    Read the article

  • How to map to tables in database PHPMyAdmin

    - by thegrede
    I'm working now on a project which a user can save their own coupon codes on the websites, so I want to know what is the best to do that, Lets say, I have 1 table with the users, like this, userId | firstName | lastName | codeId and then I have a table of the coupon codes, like this, codeId | codeNumber So what I can do is to connect the codeId to userId so when someone saves the coupons goes the codeId from the coupon table into the codeId of the users table, But now what if when a user have multiple coupons what do I do it should be connected to the user? I have 2 options what to do, Option 1, Saving the codeId from coupons table into the codeId of users table like 1,2,3,4,5, Option 2 To make a new row into the coupons table and to connect the user to the code with adding another field in the coupon table userId and putting into it the user which has added the coupon his userId of the users table, So what of the two options is better to do? Thanks you guys.

    Read the article

  • Insert Data from to a table

    - by Lee_McIntosh
    I have a table that lists number of comments from a particular site like the following: Date Site Comments Total --------------------------------------------------------------- 2010-04-01 00:00:00.000 1 5 5 2010-04-01 00:00:00.000 2 8 13 2010-04-01 00:00:00.000 4 2 7 2010-04-01 00:00:00.000 7 13 13 2010-04-01 00:00:00.000 9 1 2 I have another table that lists ALL sites for example from 1 to 10 Site ----- 1 2 ... 9 10 Using the following code i can find out which sites are missing entries for the previous month: SELECT s.site from tbl_Sites s EXCEPT SELECT c.site from tbl_Comments c WHERE c.[Date] = DATEADD(mm, DATEDIFF(mm, 0, GetDate()) -1,0) Producing: site ----- 3 5 6 8 10 I would like to be able to insert the missing sites that is listed from my query into the comments table with some default values, i.e '0's Date Site Comments Total --------------------------------------------------------------- 2010-04-01 00:00:00.000 3 0 0 2010-04-01 00:00:00.000 5 0 0 2010-04-01 00:00:00.000 6 0 0 2010-04-01 00:00:00.000 8 0 0 2010-04-01 00:00:00.000 10 0 0 the question is, how did i update/insert the table/values? cheers, Lee

    Read the article

  • Why does a change of Session State provider lead to an ASPx page yielding garbage?

    - by Rory Becker
    I have an aspnet webapp which has worked very well up until now. I was recently asked to explore ways of making it scale better. I found that seperation of database and Webapp would help. Further I was told that if I changed my session providing mechanism to SQLServer, I would be able to duplicate the Web Stack to several machines which could each call back to the state server allowing the load to be distirbuted better. This sounds logical. So I created an ASPState database using ASPNet_RegSQL.exe as detailed in many locations across the web and changed the web.config on my app from: <sessionState mode="InProc" cookieless="false" timeout="20" /> To: <sessionState mode="SQLServer" sqlConnectionString="Server=SomeSQLServer;user=SomeUser;password=SomePassword" cookieless="false" timeout="20" /> Then I addressed my app, which presented me with its logon screen and I duly logged in. Once in I was presented, not with the page I was expecting, but with: I can change the sessionstate back and forth. This problem goes away and then comes back based on which set of configuration I use. Why is this happening?

    Read the article

  • ibatis/Oracle - SELECT query inside INSERT is failing

    - by whoopy_whale
    Hi, I'm trying to do an Insert operation using iBatis. INSERT INTO SCHEMA.TABLE (FIELD1, FIELD2, FIELD3) VALUES (#field1#, (SELECT ANOTHER_FIELD FROM SCHEMA.TABLE WHERE FIELD4= #field2#), #field2#) The inner select query always fails and returns NULL. But if I substitute #field2# with the actual value only in the inner query, it works fine. Why is iBatis not substituting fieldvalues in the innerqueries? Any ideas?

    Read the article

  • SQLce Select query problem

    - by DieHard
    Wrote a Truck show Contest voting app, financial etc using sqlite. decided to write backup app for show day using ce 3.5. Created db moved to data directory, created tables configured dgridviews all is well. Entered some test data started management studio 08 ran select query against table and got null returns. Started app from vs studio and found that test data is gone. Re entered data ran query in MS data gone again. If I use VS Studio can start and enter data, close app restart and data is still there, seems only when using outside tool on select query data deletes. I don't know ce that well but this cannot be right. select * from votes = delete * from votes??????????????

    Read the article

  • ODBC vs MySQLClient

    - by Matt
    I'm currently using ODBC to connect to my MySQL database, using C#. I've been told that using the MySql Connector would be better, and faster, and not dependent on Windows. Can someone shed some light on this please? I've been unable to find anything on the net so far

    Read the article

  • transfer database from local machine to hosting server

    - by c11ada
    hey all, im trying to transfer my database from local machine to server, im using the publish to provider wizard in visual web developer to generate a scrip, im then using the generated script on the serever database. i keep getting the following error can some one please tell where im going wrong Msg 468, Level 16, State 9, Procedure aspnet_UsersInRoles_RemoveUsersFromRoles, Line 53 Cannot resolve the collation conflict between "Latin1_General_CI_AS" and "SQL_Latin1_General_CP1_CI_AS" in the equal to operation. Msg 468, Level 16, State 9, Procedure aspnet_UsersInRoles_RemoveUsersFromRoles, Line 58 Cannot resolve the collation conflict between "Latin1_General_CI_AS" and "SQL_Latin1_General_CP1_CI_AS" in the equal to operation. Msg 468, Level 16, State 9, Procedure aspnet_UsersInRoles_RemoveUsersFromRoles, Line 87 Cannot resolve the collation conflict between "Latin1_General_CI_AS" and "SQL_Latin1_General_CP1_CI_AS" in the equal to operation. Msg 468, Level 16, State 9, Procedure aspnet_UsersInRoles_RemoveUsersFromRoles, Line 92 Cannot resolve the collation conflict between "Latin1_General_CI_AS" and "SQL_Latin1_General_CP1_CI_AS" in the equal to operation. Msg 468, Level 16, State 9, Procedure aspnet_UsersInRoles_AddUsersToRoles, Line 48 Cannot resolve the collation conflict between "Latin1_General_CI_AS" and "SQL_Latin1_General_CP1_CI_AS" in the equal to operation. Msg 468, Level 16, State 9, Procedure aspnet_UsersInRoles_AddUsersToRoles, Line 52 Cannot resolve the collation conflict between "Latin1_General_CI_AS" and "SQL_Latin1_General_CP1_CI_AS" in the equal to operation. Msg 468, Level 16, State 9, Procedure aspnet_UsersInRoles_AddUsersToRoles, Line 79 Cannot resolve the collation conflict between "Latin1_General_CI_AS" and "SQL_Latin1_General_CP1_CI_AS" in the equal to operation. Msg 468, Level 16, State 9, Procedure aspnet_UsersInRoles_AddUsersToRoles, Line 83 Cannot resolve the collation conflict between "Latin1_General_CI_AS" and "SQL_Latin1_General_CP1_CI_AS" in the equal to operation. Msg 468, Level 16, State 9, Procedure aspnet_UsersInRoles_AddUsersToRoles, Line 93 Cannot resolve the collation conflict between "Latin1_General_CI_AS" and "SQL_Latin1_General_CP1_CI_AS" in the equal to operation. Msg 15151, Level 16, State 1, Line 1 Cannot find the object 'aspnet_UsersInRoles_AddUsersToRoles', because it does not exist or you do not have permission. Msg 15151, Level 16, State 1, Line 1 Cannot find the object 'aspnet_UsersInRoles_RemoveUsersFromRoles', because it does not exist or you do not have permission. thanks

    Read the article

  • Stop the user entering ' char

    - by Phil
    I have a search page where I would like to stop the user entering a ' into textboxes, or replace it with a suitable character. Can anyone help me achieve this in asp.net vb ? For example if a user searches for O'Reilly the search crashes with error: Line 1: Incorrect syntax near 'Reilly'. Unclosed quotation mark before the character string ' '. Thanks!

    Read the article

  • username and password check linq query in c#

    - by b0x0rz
    this linq query var users = from u in context.Users where u.UserEMailAdresses.Any(e1 => e1.EMailAddress == userEMail) && u.UserPasswords.Any(e2 => e2.PasswordSaltedHash == passwordSaltedHash) select u; return users.Count(); returns: 1 even when there is nothing in password table. how come? what i am trying to do is get the values of email and passwordHash from two separate tables (UserEMailAddresses and UserPasswords) linked via foreign keys to the third table (Users). it should be simple - checking if email and password mach from form to database. but it is not working for me. i get 1 (for count) even when there are NO entries in the UserPasswords table. is the linq query above completely wrong, or...?

    Read the article

  • deleting records from multiple tables at a time with a single query in sqlserver2005

    - by sudhavamsikiran
    Hi I wanna delete records from child tables as well as parent table with in a single query. please find the query given below. here response header is the primary table and responseid is the primary key. DELETE FROM responseheader FROM responseheader INNER JOIN responsepromotion ON responseheader.responseid = responsepromotion.ResponseID INNER JOIN responseext ON responsepromotion.ResponseID=responseext.ResponseID WHERE responseheader.responseid In ('67D8B9E8-BAD2-42E6-BAEA-000025D56253') but its throwing error . can any one help me to find out the correct query

    Read the article

  • JSON VIEW using GROUP_CONCAT question

    - by Dan Beam
    Hey DBAs and overall smart dudes. I have a question for you. We use MySQL VIEWs to format our data as JSON when it's returned (as a BLOB), which is convenient (though not particularly nice on performance, but we already know this). But, I can't seem to get a particular query working right now (each row contains NULL when it should contain a created JSON object with the values of multiple JOINs). Here's the general idea: SELECT CONCAT( "{", "\"some_list\":[", GROUP_CONCAT( DISTINCT t1.id ), "],", "\"other_list\":[", GROUP_CONCAT( DISTINCT t2.id ), "],", "}" ) cool_json FROM table_name tn INNER JOIN ( some_table st ) ON st.some_id = tn.id LEFT JOIN ( another_table at, another_one ao, used_multiple_times t1 ) ON st.id = at.some_id AND at.different_id = ao.different_id AND ao.different_id = t1.id LEFT JOIN ( another_table2 at2, another_one2 ao2, used_multiple_times t2 ) ON st.id = at2.some_id AND at2.different_id = ao2.different_id AND ao2.different_id = t2.id GROUP BY tn.id ORDER BY tn.name Anybody know the problem here? Am I missing something I should be grouping by? It was working when I was only doing 1 LEFT JOIN & GROUP_CONCAT, but now with multiple JOINs / GROUP_CONCATs it's messing it up. When I move the GROUP_CONCATs from the "cool_json" field they work as expected, but I'd like my data formatted as JSON so I can decode it server-side or client-side in one step.

    Read the article

  • Convert a value based on range

    - by Chris
    I need to convert a number to another value based on a range: ie: 7 = "A" 106 = "I" I have a range like this: from to return-val 1 17 A 17 35 B 35 38 C 38 56 D 56 72 E 72 88 F 88 98 G 98 104 H 104 115 I 115 120 J 120 123 K 123 129 L 129 infinity M The values are fixed and do not change. I was thinking a lookup table would be required, but is there a way it could be done with a function on an analytics function inside of oracle?

    Read the article

  • Optimum size of transaction in Postgres?

    - by Joe
    I'm running a process that does a lot of updates ( 100,000) to a table. I have the choice between putting all the updates in a single transaction or committing transactions every 1000 or so. Ignore for the moment the case where a transaction fails and is aborted. I'm interested in the best size of transaction for memory and speed efficiency.

    Read the article

  • Modeling Tools that understand both Relational and LDAP

    - by jm04469
    I am looking to do some modeling and would like to have a tool that can capture not only a relational model like ERWIN but also allow us to easily port to LDAP as an option. NOTE: Visio can connect to an existing LDAP server and draw, but does not allow for you to model first and then deploy, unlike its relational capabilities.

    Read the article

< Previous Page | 622 623 624 625 626 627 628 629 630 631 632 633  | Next Page >