How to get column-wise constraints in SQL Server - sql-server

Question

I am using below query to get constraints on required table:
SELECT
OBJECT_NAME(o.object_id) AS ConstraintName,
SCHEMA_NAME(schema_id) AS SchemaName,
OBJECT_NAME(parent_object_id) AS TableName,
type_desc AS ConstraintType
FROM
sys.objects o
-- INNER JOIN
-- sys.columns c ON o.object_id = c.object_id
WHERE
type_desc LIKE '%CONSTRAINT'
AND OBJECT_NAME(parent_object_id)= 'All_Data_Types'
Successfully getting table-wise constraint details. But, I want column's information as well.
Could someone help me with this?
Thanks in advance

Answer 1

Fast solution for default constraint is
SELECT dc.object_id AS ConstraintID, DC.name AS ConstraintName
, O.object_id AS TableID, O.name AS TableName
, C.object_id AS ColumnID, C.name AS ColName
FROM sys.default_constraints AS DC
LEFT JOIN sys.objects AS O ON O.object_id = DC.parent_object_id
LEFT JOIN sys.columns c ON o.object_id = c.object_id AND DC.parent_column_id = c.column_id

Answer 2

For table constraints you could use something like this:
SELECT KCU.*, TC.CONSTRAINT_TYPE
FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS KCU
LEFT JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS AS TC ON TC.CONSTRAINT_SCHEMA = KCU.CONSTRAINT_SCHEMA AND TC.CONSTRAINT_NAME = KCU.CONSTRAINT_NAME

Answer 3

If you are on SQL Server 2012 or later then you can use system view sys.sysconstraints:
Contains mappings of constraints to the objects that own the
constraints within the database.
So, this query:
SELECT *
FROM sys.sysconstraints s
INNER JOIN sys.objects o ON o.object_id = s.constid
theoretically returns the same number of rows as your query. But now you have the additional information about the ID of the column on which the constraint is defined. That is column colid of sys.sysconstraints:
ID of the column on which the constraint is defined.
0 = Table constraint
Thus, using this query:
SELECT OBJECT_NAME(o.object_id) AS ConstraintName,
SCHEMA_NAME(o.schema_id) AS SchemaName,
OBJECT_NAME(o.parent_object_id) AS TableName,
o.type_desc AS ConstraintType,
COALESCE(c.COLUMN_NAME, 'Table constraint') AS ColumnName
FROM sys.sysconstraints s
INNER JOIN sys.objects o ON o.object_id = s.constid
LEFT JOIN INFORMATION_SCHEMA.COLUMNS c ON c.ORDINAL_POSITION = s.colid AND s.colid <> 0
you also get the name the column related to the constraint.

Answer 4

Here is the query. You are using INNER JOIN on wrong column_name of tables.
You used this
INNER JOIN sys.columns c ON o.object_id = c.object_id
I replaced it with
INNER JOIN sys.columns c ON o.parent_object_id = c.object_id
Now you can see the column_name as well as table_name along with constraint_details.
SELECT OBJECT_NAME(o.object_id) AS ConstraintName,
SCHEMA_NAME(schema_id) AS SchemaName,
OBJECT_NAME(parent_object_id) AS TableName,
c.name as ColumnName,
type_desc AS ConstraintType
FROM sys.objects o
INNER JOIN sys.columns c ON o.parent_object_id = c.object_id
WHERE type_desc LIKE '%CONSTRAINT';
Also avoid using the below clause
AND OBJECT_NAME(parent_object_id)= 'All_Data_Types'