How can you determine the primary key using SQL? - Revision history

Connor at 14:45, 12 July 2012

2012-07-12T14:45:02Z

Connor at 09:16, 12 July 2012

2012-07-12T09:16:12Z

Connor: Created page with "How can you determine the primary key using SQL?

If you have access to the SQL code which created the table the primary key can be seen easily. The prim..."

2012-07-12T08:23:18Z

Created page with "How can you determine the primary key using SQL? <div class='ht'> <div> If you have access to the SQL code which created the table the primary key can be seen easily. The prim..."

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How can you determine the primary key using SQL?
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If you have access to the SQL code which created the table the primary key can be seen easily. The primary key may be specified in one of two ways:

CREATE TABLE cia (name VARCHAR(10) PRIMARY KEY,
population INTEGER)

or, where the primary key is composite:

CREATE TABLE casting(movieid INTEGER,
actorid INTEGER,
PRIMARY KEY (movieid, actorid)
)

If this is not possible then implementation specific commands may work.
</div>
<source lang=sql class='tidy'>
</source>
<source lang='sql' class='def e-postgres'>SELECT conkey
FROM pg_constraint JOIN pg_class
ON pg_class.oid=conrelid
WHERE contype='p'
AND relname = 'casting'
</source>
<source lang='sql' class='def e-oracle'>SELECT a.owner, a.table_name, b.column_name
FROM all_constraints a, all_cons_columns b
WHERE a.constraint_type='P'
AND a.constraint_name=b.constraint_name
AND a.table_name = 'CASTING'
</source>
<source lang='sql' class='def e-sqlserver'>sp_pkeys @table_name=casting
</source>
<source lang='sql' class='def e-mysql'>DESCRIBE casting
</source>
<div class="ecomm e-postgres" style="display: none">The array returned indicates which fields contribute to the primary key. {1,2} means that the first and second field of casting contribute to the primary key. </div>
<div class="ecomm e-oracle" style="display: none">We can use the system tables: '''all_constraints''' and '''all_cons_columns'''. For a primary key the constraint_type is 'P'. We also need the all_cons_columns view to find the actual columns. </div>
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 If you have access to the SQL code which created the table the primary key can be seen easily. The primary key may be specified in one of two ways:

How can you determine the primary key using SQL? - Revision history

Connor at 14:45, 12 July 2012

Connor at 09:16, 12 July 2012

Connor: Created page with "How can you determine the primary key using SQL? If you have access to the SQL code which created the table the primary key can be seen easily. The prim..."

Connor: Created page with "How can you determine the primary key using SQL?

If you have access to the SQL code which created the table the primary key can be seen easily. The prim..."