unique constraint null sql server 2008

You cannot create a UNIQUE constraint and allow NULLs. In the Microsoft wor...

You cannot create a UNIQUE constraint and allow NULLs. In the Microsoft world of SQL Server however, a single NULL is allowed but.

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Microsoft SQL Server introduces filtered indexes, allowing you to create an...

Microsoft SQL Server introduces filtered indexes, allowing you to create an T1(col1 INT NULL, col2 VARCHAR(10) NOT NULL);. Suppose that you want to enforce a unique constraint with multiple NULLs on col1.

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According to the ANSI standards SQL, SQL, and SQL, a UNIQUE constraint shou...

According to the ANSI standards SQL, SQL, and SQL, a UNIQUE constraint should disallow duplicate non-NULL values, but allow multiple NULL.

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This allows more than one NULL value because those rows are The implementat...

This allows more than one NULL value because those rows are The implementation of a unique constraint or index in sql server allows one Microsoft have continued this behaviour, I guess for backwards compatibility.

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I think your database is suffering from a bad data model. You might want to...

I think your database is suffering from a bad data model. You might want to rethink it a little, judging from the tables you've mentioned the model.

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The table A contains a column CIN with unique constraint but mutliple null ...

The table A contains a column CIN with unique constraint but mutliple null values. The problem is that SQL Server is rejecting the data. Is there.

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SQL Server Unique Constraint Multiple Null Values. When two rows are insert...

SQL Server Unique Constraint Multiple Null Values. When two rows are inserted with NULL values into UNIQUE index column, SQL Server throws . any version of SQL, when it comes to SQL Server we have another.

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If columns with UNIQUE constraints do not also have NOT NULL Unfortunately,...

If columns with UNIQUE constraints do not also have NOT NULL Unfortunately, Microsoft didn't true up SQL Server completely to this standard in their Regardless of the ANSI_NULLS setting, SQL Server treats Null as a.

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Unique constraint will accept only 1 NULL value but in my situation it shou...

Unique constraint will accept only 1 NULL value but in my situation it should be able to In SQL Server and later, use a filtered index.

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Change UNIQUE constraint to allow multiple NULL values # Closed .. Ok I onl...

Change UNIQUE constraint to allow multiple NULL values # Closed .. Ok I only have access to the database with Microsoft SQL Server.

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3) The unique constraint is not satisfied if and only if Most of the compla...

3) The unique constraint is not satisfied if and only if Most of the complainers were apparently thinking of Microsoft SQL Server. See, for example, NULL in unique index (where SQL Server gets it wrong) and Change.

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UNIQUE constraints allow SQL Server administrators to specify a column Use ...

UNIQUE constraints allow SQL Server administrators to specify a column Use a UNIQUE constraint when a column permits null values.

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However whilst the unique index/constraints do allow null values SQL its ea...

However whilst the unique index/constraints do allow null values SQL its easy you just have a filtered index that excludes NULL values.

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SQL Server / Oracle / MS Access: CREATE TABLE Persons (ID int NOT NULL UNIQ...

SQL Server / Oracle / MS Access: CREATE TABLE Persons (ID int NOT NULL UNIQUE, LastName varchar() NOT NULL, FirstName varchar(), Age int);.

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I see that SQL Server allows you to define a UNIQUE constraint on a column ...

I see that SQL Server allows you to define a UNIQUE constraint on a column but I also TOTALCYLINDERS TINYINT NOT NULL, Last Update:

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