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Drop all tables whose names begin with a certain string

Drop all tables whose names begin with a certain string

"How can I drop all tables whose names begin with a given string?

I think this can be done with some dynamic SQL and the INFORMATION_SCHEMA tables."

Asked by: Guest | Views: 113
Total answers/comments: 4
Guest [Entry]

"You may need to modify the query to include the owner if there's more than one in the database.

DECLARE @cmd varchar(4000)
DECLARE cmds CURSOR FOR
SELECT 'drop table [' + Table_Name + ']'
FROM INFORMATION_SCHEMA.TABLES
WHERE Table_Name LIKE 'prefix%'

OPEN cmds
WHILE 1 = 1
BEGIN
FETCH cmds INTO @cmd
IF @@fetch_status != 0 BREAK
EXEC(@cmd)
END
CLOSE cmds;
DEALLOCATE cmds

This is cleaner than using a two-step approach of generate script plus run. But one advantage of the script generation is that it gives you the chance to review the entirety of what's going to be run before it's actually run.

I know that if I were going to do this against a production database, I'd be as careful as possible.

Edit Code sample fixed."
Guest [Entry]

"SELECT 'DROP TABLE ""' + TABLE_NAME + '""'
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE '[prefix]%'

This will generate a script.

Adding clause to check existence of table before deleting:

SELECT 'IF OBJECT_ID(''' +TABLE_NAME + ''') IS NOT NULL BEGIN DROP TABLE [' + TABLE_NAME + '] END;'
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE '[prefix]%'"
Guest [Entry]

"This will get you the tables in foreign key order and avoid dropping some of the tables created by SQL Server. The t.Ordinal value will slice the tables into dependency layers.

WITH TablesCTE(SchemaName, TableName, TableID, Ordinal) AS
(
SELECT OBJECT_SCHEMA_NAME(so.object_id) AS SchemaName,
OBJECT_NAME(so.object_id) AS TableName,
so.object_id AS TableID,
0 AS Ordinal
FROM sys.objects AS so
WHERE so.type = 'U'
AND so.is_ms_Shipped = 0
AND OBJECT_NAME(so.object_id)
LIKE 'MyPrefix%'

UNION ALL
SELECT OBJECT_SCHEMA_NAME(so.object_id) AS SchemaName,
OBJECT_NAME(so.object_id) AS TableName,
so.object_id AS TableID,
tt.Ordinal + 1 AS Ordinal
FROM sys.objects AS so
INNER JOIN sys.foreign_keys AS f
ON f.parent_object_id = so.object_id
AND f.parent_object_id != f.referenced_object_id
INNER JOIN TablesCTE AS tt
ON f.referenced_object_id = tt.TableID
WHERE so.type = 'U'
AND so.is_ms_Shipped = 0
AND OBJECT_NAME(so.object_id)
LIKE 'MyPrefix%'
)
SELECT DISTINCT t.Ordinal, t.SchemaName, t.TableName, t.TableID
FROM TablesCTE AS t
INNER JOIN
(
SELECT
itt.SchemaName AS SchemaName,
itt.TableName AS TableName,
itt.TableID AS TableID,
Max(itt.Ordinal) AS Ordinal
FROM TablesCTE AS itt
GROUP BY itt.SchemaName, itt.TableName, itt.TableID
) AS tt
ON t.TableID = tt.TableID
AND t.Ordinal = tt.Ordinal
ORDER BY t.Ordinal DESC, t.TableName ASC"
Guest [Entry]

"On Oracle XE this works:

SELECT 'DROP TABLE ""' || TABLE_NAME || '"";'
FROM USER_TABLES
WHERE TABLE_NAME LIKE 'YOURTABLEPREFIX%'

Or if you want to remove the constraints and free up space as well, use this:

SELECT 'DROP TABLE ""' || TABLE_NAME || '"" cascade constraints PURGE;'
FROM USER_TABLES
WHERE TABLE_NAME LIKE 'YOURTABLEPREFIX%'

Which will generate a bunch of DROP TABLE cascade constraints PURGE statements...

For VIEWS use this:

SELECT 'DROP VIEW ""' || VIEW_NAME || '"";'
FROM USER_VIEWS
WHERE VIEW_NAME LIKE 'YOURVIEWPREFIX%'"