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• Efficient way to update all rows in a table

  - by m_pGladiator

  Hi, I have a table with a lot of records (could be more than 500 000 or 1 000 000). I added a new column in this table and I need to fill a value for every row in the column, using the corresponding row value of another column in this table. I tried to use separate transactions for selecting every next chunk of 100 records and update the value for them, but still this takes hours to update all records in Oracle10 for example. What is the most efficient way to do this in SQL, without using some dialect-specific features, so it works everywhere (Oracle, MSSQL, MySQL, PostGre etc.)?

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• Making linq avoid using in memory filtering where possible

  - by linqmonkey

  Consider the these two LINQ2SQL data retrieval methods. The first creates a 'proper' SQL statement that filters the data, but requires passing the data context into the method. The second has a nicer syntax but loads the entire list of that accounts projects, then does in memory filtering. Is there any way to preserve the syntax of the second method but with the performance advantage of the first? public partial class Account { public IQueryable<Project> GetProjectsByYear(LinqDataContext context, int year) { return context.Projects.Where(p => p.AccountID==this.AccountID && p.Year==year).OrderBy(p => p.ProjectNo) } public IQueryable<Project> GetProjectsByYear(int year) { return this.Projects.Where(p => p.Year==year).OrderBy(p => p.ProjectNo).AsQueryable() } }

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• Mapping LINQ to SQL table to another very similar table without iterating through every one

  - by Daniel Coffman

  Apologies for the vague question. Here it is: I have a table object created by LINQ to SQL. I am copying entries from one table to an "archive" table that has all the columns of the original, plus a couple extra ones. It feels sloppy to iterate through every object and manually define the mapping like: foreach (oldTable in dbContextOldTables) { var newTable = new NewTable(); newTable.TableID = oldTable.ID; newTable.Title = oldTable.Title; ... (repeat for twenty columns) newTable.ColumnThatIsntInOldTable = "Data that will be the same for every row"; dbContext.NewTables.InsertOnSubmit(newTable); } dbContext.SubmitChanges(); Is there a clever way to do this?

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• LinqToSql Sub Entiity Multiple And Operators

  - by halit

  Hi I have an Array of Featureset Id , My Vehicles table has got sub table as FeatureSets I wrote Sql Query Like SELECT [t0].[ID] FROM [dbo].[SearchResultView] AS [t0] Join [dbo].[VehicleFeatureSet] AS [t1] on t0.ID = t1.VehicleID where t1.FeatureSetID = 1 and t1.FeatureSetID= 2 and t1.FeatureSetID= 3 I tried. But I Couldn't var features = Request.QueryString["FeatureSets"].Split(',').ToList().ConvertAll(new Converter<string, int>(StrinToint)); IQueryable<SearchResultView> result = db.SearchResultViews.Where(m => m.Active == true); foreach (var featuree in features) { result = result.Where(m => m.VehicleFeatureSets.Any(c => c.FeatureSetID == featuree)); } How Can I write this LINQ Query

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• Performance: Subquerry or Joining

  - by Auro

  HelloHello I got a little Question about Performance of a Subquerry /Joining another table INSERT INTO Original.Person ( PID, Name, Surname, SID ) ( SELECT ma.PID_new , TBL.Name , ma.Surname, TBL.SID FROM Copy.Person TBL , original.MATabelle MA WHERE TBL.PID = p_PID_old AND TBL.PID = MA.PID_old ); This is my SQL, now this thing runs around 1 million times or more. Now my question is what would be faster? if I change TBL.SID to (Select new from helptable where old = tbl.sid) or if I add helptable to the from and do the joining in the where? greets Auro

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• Database design to hold multiple iteration measurements

  - by Valder

  Hi All. I am new to sqlite and SQL in general. I am keen to switch from flat-files to sqlite for holding some measurement information. I need a tip on how to better layout the database, since I have zero experience with this. I have a ~10000 unique statistic counters that are collected before and after each test iteration. Max number of iterations are 10, though it could be less. I was thinking the following: CREATE TABLE stat_names(stat_id, stat_name); CREATE TABLE stats_per_iteration(stat_id, before_iter_1, after_iter_1, before_iter_2, after_iter_2, ...); stat_names table would hold mapping of a full counter to a uniq stat_id. stats_per_iteration table would hold mesurement data 1 + 10 * 2 columns. stat_names.stat_id = stats_per_iteration.stat_id OR maybe I should have a separate table for each iteration? Which would results in 1 + 10 tables in database. Thanks!

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• Debugging (displaying) SQL command sent to the db by SQLAlchemy

  - by morpheous

  I have an ORM class called Person, which wraps around a person table: After setting up the connection to the db etc, I run the ff statement. people = session.query(Person).all() The person table does not contain any data (as yet), so when I print the variable people, I get an empty list. I renamed the table referred to in my ORM class People, to people_foo (which does not exist). I then run the script again. I was surprised that no exception was thrown when attempting to access a table that does not exist. I therefore have the following 2 questions: How may I setup SQLAlchemy so that it propagates db errors back to the script? How may I view (i.e. print) the SQL that is being sent to the db engine If it helps, I am using PostgreSQL as the db

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• Log your SQL in Rails application inside unit test

  - by Phuong Nguy?n

  I want to install a logger so that I can dump all executed SQL of my rails application. Problem is, such logger is associated with AbstractAdapter which initialized very soon under test mode, and thus cannot be set by my initializer code. I try to put ActiveRecord::Base.logger = MyCustomLogger.new(STDOUT) in the end of environment.rb like someone advised but it only works when being run in console environment (kicked by script/console), not when run under test mode. I wonder if there is any way to config such logger so that I will sure to be invoked under any environment (test, development, production, console)

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• Database Backup

  - by Jungle_hacker

  Scenario i want to take backup from 7 client database to 1 server database. i dont know structure of the db { either server or client db }. both databases are having old data. now i have to make the tool take the backup for that. and should possible to backup old data also[if any updates done on old data.] please help to find the solution for this. 1. how can i proceed with the problem. 2. database not specified, may be MS access or Sql server 2005 3. In which i can implement this [ I am thinking of doing it in c#] please help me to find the solution

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• Username correct, password incorrect?

  - by jonnnnnnnnnie

  In a login system, how can you tell if the user has entered the password incorrectly? Do you perform two SQL queries, one to find the username, and then one to find the username and matching (salted+hashed etc) password? I'm asking this because If the user entered the password incorrectly, I want to update the failed_login_attempts column I have. If you perform two queries wouldn't that increase overhead? If you did a query like this, how would you tell if the password entered was correct or not, or whether the username doesn't exist: SELECT * FROM author WHERE username = '$username' AND password = '$password' LIMIT 1 ( ^ NB: I'm keeping it simple, will use hash and salt, and will sanitize input in real one.) Something like this: $user = perform_Query() // get username and password? if ($user['username'] == $username && $user['password'] == $password) { return $user; } elseif($user['username'] == $username && $user['password'] !== $password) { // here the password doesn't match // update failed_login_attemps += 1 }

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• datediff rounding

  - by derekcohen

  I have a db table in SQL Server which contains a start date for a project. On a web status page I want to show how many days/weeks/months the project has run, the units depending on the duration. So under 21 days I'd show days, under 7 weeks I'd show weeks, otherwise show completed months. So I get the days, weeks and months values and can then use some code to decide which one to display. Suppose the project starts on 30 Dec 2010 and I'm checking today (27 Feb 2011). select datediff(d,'30 Dec 2010',getdate()) as days, datediff(wk,'30 Dec 2010',getdate()) as weeks , datediff(m,'30 Dec 2010',getdate())as months produces days: 59 weeks: 9 months: 2 But in fact the difference is 8 whole weeks and some rounding takes place. I've tried doing it in ASP as well, getting the start date and then doing the datediff() but it's no better. Is there a better way? thanks

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• C# SQL SELECT Statement

  - by Feren6

  I have the following code: SqlCommand cmd2 = new SqlCommand("SELECT ClaimId FROM tblPayment WHERE PaymentId = " + PaymentID.ToString(), mvarDBConn); SqlDataReader reader = cmd2.ExecuteReader(); reader.Read(); Int32 ClaimId = reader.GetInt32(0); reader.Close(); If I run the SELECT statement in SQL it returns the number fine, but when I use ExecuteReader all it returns is 0. I've tried multiple methods including ExecuteScalar, ExecuteNonQuery, reader.GetString then casting that to an int, etc. What am I missing? Thanks.

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• Seeking assistance with Escaping Data for MySQL queries

  - by JM4

  Please don't send me a link to php.net referencing mysql_real_escape_string as the only response. I have read through the page and while I understand the general concepts, I am having some trouble based on how my INSERT statement is currently built. Today, I am using the following: $sql = "INSERT INTO tablename VALUES ('', '$_SESSION['Member1FirstName'], '$_SESSION['Member1LastName'], '$_SESSION['Member1ID'], '$_SESSION['Member2FirstName'], '$_SESSION['Member2LastName'], '$_SESSION['Member2ID'] .... and the list goes on for 20+ members with some other values entered. It seems most people in the examples already have all their data stored in an array. On my site, I accept form inputs, action="" is set to self, php validation takes place and if validation passes, data is stored into SESSION variables on page 2 then redirected to the next page in the process (page 3) (approximately 8-10 pages in the whole process). thanks!

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• Stored procedure for selecting multiple records

  - by padmavathi

  I need to select records say 2000 from a table with a matching timestamp from c# .net code. Eg: SELECT * FROM ITEMDATA_TABLE WHERE ITEMNAME='Item1' and TimeStamp='2010-04-26 17:15:05.667' The above query has to execute for 2000 items more for the same timestamp. for this we can use SELECT * FROM ITEMDATA_TABLE WHERE ITEMNAME in ('Item1','Item2','Item3','Item4',......) AND TimeStamp='2010-04-26 17:15:05.667' from SQL Server Management Studio. I have tried appending all Item names to one string variable and giving it as a parameter to the stored procedure,but it resulted into a wrong concatenation. How can I do this as a stored procedure executing from the .net code? Can anyone suggest me/correct me in doing this? Thanks & Regards Padma

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• Computed Column with relationships

  - by Sethery

  I have a table, MapLocation, which has a column and two relationships with tables that have a field that really need to be displayed as a single concatenated value. I was thinking this was a perfect case for a computed column, but not sure how to go about it. MapLocation MaoNo Section _____________________ _____________________ _____________________ MapNoId MapNoId SectionId SectionId MapNumber (int) Section (int) Identifier (nvarchar) LocationName (nvarchar) LocationName = "MapNUmber - SectionNumber - Identifier" ex: 20 - 03 - SW4 How would I write that? I haven't done much with computed columns or concatenating in SQL. Edit: I need an actual computed column that is automatically updated, im looking for the formula. Or is this more of a function/trigger? Its possible, I certainly barely know what I'm doing. The idea is that I dont want to have to do two more server calls and concatenate these values client side.

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• How to create a MySQL query for time based elements with a 'safe window'?

  - by pj4533

  I am no SQL expert, far from it. I am writing a Rails application, and I am new at that as well. I come from a desktop programming background. My application has a table of data, one of the columns is the time at which the data was logged. I want to create a query with a 'safe window' around EACH row. By that I mean, it returns the first row, then for X minutes (based on the timelogged column) it won't return any data, once X minutes is up, it will return the next row. For example: ID | TimeLogged 1 | 3/5/2010 12:01:01 2 | 3/5/2010 12:01:50 3 | 3/5/2010 12:02:03 4 | 3/5/2010 12:10:30 5 | 3/5/2010 01:30:03 6 | 3/5/2010 01:31:05 With a 'safe window' of 5 minutes I want to create a query to return: 1 | 3/5/2010 12:01:01 4 | 3/5/2010 12:10:30 5 | 3/5/2010 01:30:03 (It skipped the 12:01:50 and 12:02:03 items because they occurred within 5 minutes of the first item.) Another example, with a 'safe window' of 15 minutes I want to return: 1 | 3/5/2010 12:01:01 5 | 3/5/2010 01:30:03 Perhaps I have to just return all data and parse it myself?

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• Deadlock Problem because of an Update Lock.

  - by Randy Minder

  We have a deadlock issue we're trying to track down. I have an deadlock graph (xdl) generated from Profiler. It shows the losing SQL statement as a simple Select statement, not an Update, Delete or Insert statement. The graph shows the losing Select statement as requesting a Shared lock on a resource **but also owning an Update lock on a resource**. This is what is baffling me. Why would a Select statement that is not part of an Insert, Update or Delete ever hold an Update lock on a resource? I should add that the Update lock it owns is on the table being selected against by the losing Select statement.

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• How Do I Execute A Stored Procedure From A BizTalk SendPort?

  - by kgarske

  Hello, I would like to call a stored procedure from a SendPort. I want to avoid an orchestration and instead, create a subscription to the message box based on the receive port and message type. I also need to use attributes from the received message xml as parameters for my stored procedure. My assumption is that I should use WCF-SQL adapter. However, the only examples I have found require a 20 step process and some magic/luck... oh yeah, and an orchestration. Am I crazy for thinking this should be way simpler than it seems? Can anyone provide me with resources or advice?

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• Application Role and access second database

  - by lszk

  I have written a script to create an audit trails to my database in a second one db. So far I had no problems during tests on my dev machine from SQL Server Management Studio. Problems started to occurs when I first tried to test my triggers from my application by modyfing data in it. Using profiler I found out, that my audit trails db is not visible in sys.databases, so here lies the problem. The application using an Application Role, so as I found on MSDN, that's why I can't get access to other db on the server. I'm not a DBA. I have no experience with properly settings the security stuff, so please guide me, how can I set the setting for guest account (according to MSDN) to get access to this db? I need to have a record for this database in sys.databases and I need to be able to insert data in this database in all tables. No select, update or delete I need.

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• declare and assign value my sql stored procedure(5.0.45)

  - by naveen84n

  Hi everybody , DELIMITER $$ DROP PROCEDURE IF EXISTS quotations.sp_addservices $$ CREATE PROCEDURE quotations.sp_addservices (In categoryname varchar(25),in servicename varchar(250),in hours float,in cost float,in basis nvarchar (100)) BEGIN insert into categorydetails (Category_Name) values (categoryname); if(categoryname!=null) then DECLARE category_id int; set category_id= select max(Category_Id) from categorydetails ; insert into servicesdetails (Service_Name,Category_Id,Hours,Cost,Basis) values(servicename,category_id,hours,cost,basis); end if; END $$ DELIMITER ; This is my stored procedure .I have to retrive the value of categoryid that is posted into the database which is auto increased.Here i cant declare the variable and assign value to variable.Am getting error like Script line: 4 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DECLARE category_id int; set category_id= select max(Category_Id) from categor' at line 9 Can any one help me Thanks in advance.

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• If statement in MySQL query with PHP

  - by user1104854

  Is it possible to use an if statement in a MySQL query in a similar what I'm showing? I want to grab some information for upcoming events(not ones with previous dates). ini_set('date.timezone', 'America/New_York'); $timestamp = date('m/d/Y'); $sql = "select eventID,eventTitle,eventDate from events where eventLocationID = $locationID ORDER BY eventDate DESC IF(eventDate > $timestamp) "; I really want to avoid doing post-query if statements that will only print if it's after today's date because I run it through a pagination function, and I'd really prefer to avoid tinkering with that.

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• EF - Entity Sql contains clausule with string

  - by zikrija

  Hi all, I have one question about EF. If I understand correctly EF does not support Contains. I try to achieve this: I have column(nvarchar) with this: for ex.row1. 1;3;4;5,row2. 3;4;6 row3. 7;8;16 etc. I have list(of string) with 1,6. My goal is to get row1 and row2 in result set. I try with linq to entity and with linq to sql but i can't get this right. I stuck with this and any help would be appreciated... Tnx

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• exec sp_executesql error 'Incorrect syntax near 1' when using datetime parameter

  - by anne78

  I have a Ssrs report which sends the following text to the database : EXEC ( 'DECLARE @TeamIds as TeamIdTableType ' + @Teams + ' EXEC rpt.DWTypeOfSicknessByCategoryReport @TeamIds , ' + @DateFrom + ', ' + @DateTo + ', ' + @InputRankGroups + ', ' + @SubCategories ) When I view this in profiler it interprets this as : exec sp_executesql N'EXEC ( ''DECLARE @TeamIds as TeamIdTableType '' + @Teams + '' EXEC rpt.DWTypeOfSicknessByCategoryAndEmployeeDetailsReport @TeamIds, '' + @DateFrom + '', '' + @DateTo + '', '' + @InputRankGroups + '', '' + @SubCategories )',N'@Teams nvarchar(34),@DateFrom datetime,@DateTo datetime,@InputRankGroups varchar(1),@SubCategories bit',@Teams=N'INSERT INTO @TeamIds VALUES (5); ',@DateFrom='2010-02-01 00:00:00',@DateTo='2010-04-30 00:00:00',@InputRankGroups=N'1',@SubCategories=1 When this sql runs it errors, on the dates. I have tried changing the format of the date but it does not help. If I remove the dates it works fine. Any help would be appreciated.

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• Need help with some complex SQL query

  - by Psyche

  Hello guys, I need some help with a complex SQL query. Here's my setup: there are two tables, one with authors, and another with books. The books table contains a field named "author" which holds author's id. If a book has more than one author, then the "author" field will contain all the authors ids separated by ";" (something like 2;34;234). On the website I have to list all the books written by an author. If there's only one author, its simple, but how can I get those books where the author I'm interested in is the second or third author? Many thanks.

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• Index out of range exception when using this query from C#

  - by jenifa

  I am using a calculation in my SQL query. How can I use that calculated field in C#? When I try, I get an index out of range exception. My query is: Select OwnerCompanyLog.olog_name,inlt_companyid,inlt_childcompid,inlt_effectinterest,inlt_percent,inlt_sharetype,inlt_shares,inlt_childbase,inlt_effdate, (inlt_percent * inlt_effectinterest)/100)eff from InterestLogTable INNER JOIN OwnerCompanyLog ON InterestLogTable.inlt_childcompid = OwnerCompanyLog.olog_companyid where inlt_companyid=5 Order By inlt_childcompid I want to use inlt_percent * inlt_effectinterest)/100 in my C# code: entity.ParentCompany = new List<Company>(); while (parentCompanyReader.Read()) { ParentCompany.Effect = parentCompanyReader["eff"].ToString(); entity.ParentCompany.Add(ParentCompany); } parentCompanyReader.Close(); But I got the error above.

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