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POSQL-Server Query on the Results of Itself
 

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    <p>I'm trying to identify the risks in deleting tables from my database.</p> <p>The database is large and contains hundreds of tables.</p> <p>I have a query that returns Foreign Keys associated with a table. So I can feed it table names I want to delete and it tells me what tables rely on columns it has. So I will also have to delete the tables that are returned.</p> <p>My problem comes that as I would then need to delete those tables, I'd like to see any other tables that depend on the initial results.</p> <p>As such I believe I need my query to loop calling itself with the results of it's last run, until there are no more unique results.</p> <p>Is this possible? Is there an easier way of doing this?</p> <p>EDIT: Here's the query:</p> <pre><code>SELECT PK.TABLE_NAME AS PrimaryTable, FK.TABLE_NAME AS ForeignTable, PT.COLUMN_NAME AS PrimaryColumn, CU.COLUMN_NAME AS ForeignColumn, C.CONSTRAINT_NAME AS ConstraintName FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS C INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS FK ON C.CONSTRAINT_NAME = FK.CONSTRAINT_NAME INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS PK ON C.UNIQUE_CONSTRAINT_NAME = PK.CONSTRAINT_NAME INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE CU ON C.CONSTRAINT_NAME = CU.CONSTRAINT_NAME INNER JOIN ( SELECT i1.TABLE_NAME, i2.COLUMN_NAME FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS i1 INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE i2 ON i1.CONSTRAINT_NAME = i2.CONSTRAINT_NAME WHERE i1.CONSTRAINT_TYPE = 'PRIMARY KEY' ) PT ON PT.TABLE_NAME = PK.TABLE_NAME WHERE PK.TABLE_NAME IN ('Table1','Table2') ORDER BY 1,2,3,4 </code></pre>
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    1. USTom.Bowen89
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    1. COCan you post the query itself? You might be able to use a recursive CTE to do the looping. It is useful for hierarchies.
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      1. USMatt
    2. COI've edited it into the question. I've thought and read about CTE's but not had much experience in them.
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    3. COHow do you handle the propagation of changes through triggers? Or do you scan for triggers and opt not to run if any are defined?
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      1. USHABO
 

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