Sql-server – Warning SQL01271: The unnamed foreign key between tables [dbo].[Match] and [dbo].[Team] will be checked by checking the table

sql-server-2008visual studio 2010

I received this error while deploying a SQL Server DBProject

DBProj.dbschema(0,0): Warning SQL01271: The unnamed foreign key
between tables [dbo].[Match] and [dbo].[Team] will be checked by
checking the table. Name the foreign key to avoid checking the entire
table and only check the new constraint.

My table definition is

CREATE TABLE [dbo].[Match]
(
    MatchID         int identity(11,2) PRIMARY KEY, 
    TournamentID    int not null REFERENCES Tournament(TournamentID),
    Team1_ID        int not null REFERENCES Team(TeamID),
    Team2_ID        int not null REFERENCES Team(TeamID),
    MatchDate       date,
    MatchTime       time
)

What does this error means? What is the implication?

update

actually, am concerned about the warning that it will check the
entire table. Is it at creation time or every time? how does this
affect performance?

Best Answer

Try the more verbose syntax

...
Team1_ID int not null CONSTRAINT FK_Match_Team1 FOREIGN KEY (TeamID) REFERENCES Team (TeamID),
Team1_ID int not null CONSTRAINT FK_Match_Team2 FOREIGN KEY (TeamID) REFERENCES Team (TeamID),
...

I'd suggest the lack of explicit constraint name is confusing VS because you have 2 match-team constraints. That is, it is a Visual Studio error not a SQL Server error. You won't get it in SSMS

Related Solutions

Sql-server – How to get the foreign and primary key details for a table in SQL Server 2008

You should become familiar with the new catalog views. The old sysobjects, syscolumns etc. have been deprecated and are only provided for backward compatibility reasons - they shouldn't be used for new development and old code should eventually transition to the new objects.

Here is a query that will get both sides of the columns involved in foreign keys:

SELECT 
        constraint_name   = OBJECT_NAME(fkc.constraint_object_id), 
        foreign_schema    = SCHEMA_NAME(child.[schema_id]), 
        foreign_table     = child.name, 
        foreign_column    = child_cols.name, 
        referenced_schema = SCHEMA_NAME(referenced.[schema_id]),
        referenced_table  = referenced.name, 
        referenced_column = referenced_cols.name
    FROM sys.foreign_key_columns AS fkc
    INNER JOIN sys.tables AS child
    ON fkc.parent_object_id = child.[object_id]
    INNER JOIN sys.tables AS referenced
    ON fkc.referenced_object_id = referenced.[object_id]
    INNER JOIN sys.columns AS referenced_cols
    ON fkc.parent_column_id = referenced_cols.column_id
    AND referenced_cols.[object_id] = referenced.[object_id]
    INNER JOIN sys.columns AS child_cols
    ON fkc.referenced_column_id = child_cols.column_id
    AND child_cols.[object_id] = child.[object_id]
    WHERE referenced.name = 'table name'
    -- if you want the tables that a child table references, use this instead:
    -- WHERE child.name = 'table name'
    ORDER BY fkc.parent_column_id;

And this one is much simpler, just for the tables involved:

SELECT 
    constraint_name = name, 
    foreign_schema = OBJECT_SCHEMA_NAME(parent_object_id),
    foreign_table = OBJECT_NAME(parent_object_id), 
    referenced_schema = OBJECT_SCHEMA_NAME(referenced_object_id),
    referenced_table = OBJECT_NAME(referenced_object_id)
FROM sys.foreign_keys
WHERE OBJECT_NAME(referenced_object_id) = 'table name'
-- if you want the tables that a child table references, use this instead:
-- WHERE OBJECT_NAME(parent_object_id) = 'table name';

EDIT adding some links to documentation (these mostly fall within the SQL Server 2008 R2 hierarchy but they're roughly equivalent for SQL Server 2008 as well):

Sql-server – How to check the integrity of disabled foreign key relationships for each individual table? (SQL Server 2008)

These DBCC CHECKCONSTRAINTS commands can be run as follows:

DBCC CHECKCONSTRAINTS (TableName) - checks an individual table
DBCC CHECKCONSTRAINTS (ConstraintName) - checks an individual constraint
DBCC CHECKCONSTRAINTS WITH ALL_CONSTRAINTS - checks all constraints in the database
DBCC CHECKCONSTRAINTS WITH ALL_ERRORMSGS - returns all rows that violate constraints
DBCC CHECKCONSTRAINTS WITH NO_INFOMSGS - suppress messages when query runs
DBCC CHECKCONSTRAINTS check only enabled constraints

Keep in mind that SQL Server needs to read through all of your data to check for the constraints, so be careful not to run this across the board for your large or very busy databases. This should be something that is run off hours and also for very large databases you should run this either at a table level or a constraint level.

Best Answer

Related Solutions

Sql-server – How to get the foreign and primary key details for a table in SQL Server 2008

Sql-server – How to check the integrity of disabled foreign key relationships for each individual table? (SQL Server 2008)

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