Sql – Adding a logical key to a View in SQL Server Manager

entity-frameworksql-server-2005

The .NET Entity framework is giving me the following error:

"The table/view 'Foo.dbo.vwFoo' does not have a primary key defined and no valid primary key could be inferred. This table/view has been excluded. To use the entity you will need to review your schema, add the correct keys and uncomment it."

The view is a collection of a variety of tables and calculations. What I'd like to do is create a "logical key" using one of the columns that I know should be unique. I can't figure out how to do this in SQL Server Manager 2005 (not a DBA.)

Anyone know how I could accomplish this?

Best Answer

The EF can't find the PK, because VIEWs don't have PKs. However, if the view returns a unique column, you can tell the EF that this is the "PK."

It's explained in this tip: How to work with Updatable Views

Syntax:

ALTER TABLE {TABLENAME} 
ADD {COLUMNNAME} {TYPE} {NULL|NOT NULL} 
CONSTRAINT {CONSTRAINT_NAME} DEFAULT {DEFAULT_VALUE}
WITH VALUES

Example:

ALTER TABLE SomeTable
        ADD SomeCol Bit NULL --Or NOT NULL.
 CONSTRAINT D_SomeTable_SomeCol --When Omitted a Default-Constraint Name is autogenerated.
    DEFAULT (0)--Optional Default-Constraint.
WITH VALUES --Add if Column is Nullable and you want the Default Value for Existing Records.

Notes:

Optional Constraint Name:
If you leave out CONSTRAINT D_SomeTable_SomeCol then SQL Server will autogenerate
a Default-Contraint with a funny Name like: DF__SomeTa__SomeC__4FB7FEF6

Optional With-Values Statement:
The WITH VALUES is only needed when your Column is Nullable
and you want the Default Value used for Existing Records.
If your Column is NOT NULL, then it will automatically use the Default Value
for all Existing Records, whether you specify WITH VALUES or not.

How Inserts work with a Default-Constraint:
If you insert a Record into SomeTable and do not Specify SomeCol's value, then it will Default to 0.
If you insert a Record and Specify SomeCol's value as NULL (and your column allows nulls),
then the Default-Constraint will not be used and NULL will be inserted as the Value.

Notes were based on everyone's great feedback below.
Special Thanks to:
@Yatrix, @WalterStabosz, @YahooSerious, and @StackMan for their Comments.

Sql-server – Check if table exists in SQL Server

For queries like this it is always best to use an INFORMATION_SCHEMA view. These views are (mostly) standard across many different databases and rarely change from version to version.

To check if a table exists use:

IF (EXISTS (SELECT * 
                 FROM INFORMATION_SCHEMA.TABLES 
                 WHERE TABLE_SCHEMA = 'TheSchema' 
                 AND  TABLE_NAME = 'TheTable'))
BEGIN
    --Do Stuff
END

Best Answer

Related Solutions

Sql – Add a column with a default value to an existing table in SQL Server

Syntax:

Example:

Notes:

Sql-server – Check if table exists in SQL Server

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