SQL Server 2008: Find out primary/foreign key in Table?

Question

Does anyone know how I can see which are the primary & foreign keys in a table?

EDIT: Thanks for all the responses. I was looking for a SQL Query to do that. Rig

Answer 1

see the Querying the SQL Server System Catalog FAQ, How do I find the columns of a primary key for a specified table? and How do I find the columns of a foreign key for a specified table?

EDIT: if you want to do it programmatically (which is not clear from your question), that is.

Answer 2

In Management Studio, expand the table and then expand the Columns item. The primary key(s) has a key icon next to them.

To see the foreign keys, expand the Constraints item.

Answer 3

You can start with:

SELECT 
   Table_Name as [TableName], 
   Column_Name as [ColumnName],
   Constraint_Name as [Constraint], 
   Table_Schema as [Schema]
FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE
ORDER BY 
   [TableName], 
   [ColumnName]

(you can filter then by tableName)

Answer 4

For the primary key on each table, you can use this query:

SELECT
    kc.name,
    c.NAME
FROM 
    sys.key_constraints kc
INNER JOIN 
    sys.index_columns ic ON kc.parent_object_id = ic.object_id
INNER JOIN 
    sys.columns c ON ic.object_id = c.object_id AND ic.column_id = c.column_id
WHERE
    kc.type = 'PK'

and for the foreign key, I believe this query should get you the necessary information:

SELECT
    OBJECT_NAME(parent_object_id) 'Parent table',
    c.NAME 'Parent column name',
    OBJECT_NAME(referenced_object_id) 'Referenced table',
    cref.NAME 'Referenced column name'
FROM 
    sys.foreign_key_columns fkc
INNER JOIN 
    sys.columns c 
       ON fkc.parent_column_id = c.column_id 
          AND fkc.parent_object_id = c.object_id
INNER JOIN 
    sys.columns cref 
       ON fkc.referenced_column_id = cref.column_id 
          AND fkc.referenced_object_id = cref.object_id

Marc

Answer 5

SELECT
OBJECT_NAME(parent_object_id) 'Parent table',
c.NAME 'Parent column name',
OBJECT_NAME(referenced_object_id) 'Referenced table',
cref.NAME 'Referenced column name'
FROM 
sys.foreign_key_columns fkc 
INNER JOIN 
sys.columns c 
   ON fkc.parent_column_id = c.column_id 
      AND fkc.parent_object_id = c.object_id
INNER JOIN 
sys.columns cref 
   ON fkc.referenced_column_id = cref.column_id 
      AND fkc.referenced_object_id = cref.object_id  where OBJECT_NAME(parent_object_id) = 'tablename'

If you want to get the foreign key relation of all the tables exclude the where clause else write your tablename instead of tablename