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Select one row from a table by specifying the row number (Databse) [duplicate]

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Row numbers in query result using Microsoft Access
(7 answers)
Closed 4 years ago.
I am currently working on a C# .Net program. This program is connected to an MS Access database.
I am trying to select just one row from a table by specifying the row number, but I can not find any solution for that.
I hope you can help me with my problem :)

You should use primary key or unique column to get 1 row correct data. Other way is very manually and painfull in my opinion. Example
SELECT * FROM Customer WHERE CustomerID=1;
CostumerID is primary key and it bring 1 row to result. If do you realy want to make it manualy i advise add a datagridview in your project and make its visible to false. Fill your all data into it and get what do you want in it. You can access each row easyly.

SQL Server Add a uniqueidentifier to every table in the database [duplicate]

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Adding a column to all user tables in t-sql
(2 answers)
Closed 6 years ago.
I created a C# app with a SQL Server 2014 backend. I was only intending to use the app for myself but now I have interest from other users. I never had the forethought to add a user id to any of the tables and my question is how could generate a script to add a uniqueid column to all the tables. I don't want to create a new database for every user and would prefer that every table has a unique column for the user.

Try this :
exec sp_msforeachtable 'alter table ? add new_guid uniqueidentifier null';

newid() as column default value [duplicate]

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Entity Framework - default values doesn't set in sql server table
(4 answers)
Closed 8 years ago.
I have a table with a uniqueidentifier column.
What is the Default Value or Binding i should set in order for each new row to generate a new uniqueidentifier?
Setting the default to newid() always returns 00000000-0000-0000-0000-000000000000
EDIT:
Apparently i got it all wrong, the insert was done from Entity Framework, and it doesn't handle this scenario.
Entity Framework - default values doesn't set in sql server table

newid() should work.
See images below:
You have another issue there.

Is there a get-or-create (lazy loading?) idiom in SQL? [duplicate]

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Closed 10 years ago.
Possible Duplicate:
Solutions for INSERT OR UPDATE on SQL Server
Check if a row exists, otherwise insert
I'm using SQL Server 2008 R2, C# .NET 4.0 (and LINQ).
I want to get or create a row in a table and then append a string to one of its columns.
I'm wondering if there's a best practice for this kind of idiom, or if SQL offers this out of the box?
Somehow transaction start -> select -> insert or update -> transaction end doesn't seem elegant enough...

LINQ to SQL Primary Key requirement for inserts fails [closed]

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I'm working on better understanding Linq-to-SQL before using on a real project, so I'm playing with it on a little side project. I've a table that I'm trying to update via DataContext.SubmitChanges() and it's failing due to primary key constraints.
I have no control over the table itself (I can't add an actual ID column), so instead I've modified the Linq entity to use 3 columns as a complex key. The inserts are still failing, even though the key data is unique across both the update set and the existing data in the table, and I'm curious to know why. What am I missing that forces Linq to treat these values as non unique?
Note that I am not trying to solve the update problem itself - I've determined that in my situation DataContext.ExecuteCommand() will work just as well. I'm trying to grok where my understanding of Linq (or of my data) is wrong.
The table structure looks like this:
OPRID (char(30))
DATE (DateTime)
PROJECT_ID (char(15))
HOURS (decimal)
The last 3 columns are the complex key.
And here's some sample data, comma delimited:
cschlege, 2009-1-5, 10100, 0.8
cschlege, 2009-1-5, 10088, 1.1
cschlege, 2009-1-5, 10099, 0.8
cschlege, 2009-1-5, 10088, 1.2
The SubmitChanges() consistently fails on the last of those rows, but given a key of DATE, PROJECT_ID, HOURS those rows should be unique. It doesn't fail on the 3rd row, which has a duplication in the HOURS column, but only when it reaches the duplicate PROJECT_ID. If I remove PROJECT_ID from the complex key then the insert fails on the 3rd row, however.
Why is LINQ not treating those rows as uniquely keyed?

Given your explanation I would guess that the HOURS (decimal) is the problem ... It must be mapped somehow with a different precision.
If 1.2 rounds to 1 then you have a problem with:
cschlege, 2009-1-5, 10088, 1 (2)
cschlege, 2009-1-5, 10088, 1 (4)
As you said, if you remove the project ID you end up with failure in the 3rd row:
cschlege, 2009-1-5, 10100, 0 (1)
cschlege, 2009-1-5, 10099, 0 (3)
Can you insert just the last row in the db and then confirm that is with 1.2?

Ah. The answer is that I'm not paying close enough attention to the backing store's rules. There's a different index that's actually failing.