TEST FOR CHECK CONSTRAINT ANOMALY

SQL Server will not generate an error when creating check constraints 
at
the column or table level that are a mismatch to the datatype of the
column(s) referenced. When a check constraint is created on a column 
that is
defined with an integer datatype and the check constraint checks for
values of nonnumeric values, no error is generated. Instead, an error 
is
generated when inserts are attempted.

If you use a CASE tool to generate DDL, make sure the constraints from
domain values are appropriate for the column's datatype. It may be wise 
to
have test data values generated for each table to test for this anomaly
(especially for a database with several hundred tables, which has many
domain values defined for columns). The following script demonstrates 
this
problem.

CREATE TABLE CheckConstraint
(Pkey INT NOT NULL,
col1  INT NULL
     CONSTRAINT ck_col_check_constraint CHECK  (col1 IN ( 'a','b' ) ),
CONSTRAINT pk_CheckConstraint PRIMARY KEY (Pkey),
CONSTRAINT ck_table_check_constraint CHECK (col1 IN ('a','b'))
)
GO
INSERT CheckConstraint VALUES(1,1)
GO
EXEC sp_help CheckConstraint
GO
DROP TABLE CheckConstraint
GO

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