Monthly Archives: June 2017

How to archive tables that contain a keyword from one database to another using T-Sql

Data, Database Administrator, dba, Development, How To, SQL Server, T-SQL, tsql, , , , , , , , , , , ,

In the previous article I wrote about how to identify and remove unwanted tables. Link

In that tutorial I suggested prefixing the tables you want to remove with _DELETE_.

I also suggested you may want to archive the tables in some manner before you delete them. This could be because there is a chance someone might come looking for the data that was in a deleted table or something might break by removing the table and you might want to put it back asap.

If you have only a few tables you could script the tables out but if you have a lot of tables that becomes a little unmanageable. Also if the tables total in size to 10 Gb the script to recreate the tables will be a lot lot larger.

An alternative method is to create an Archive database, copy the tables across to this target database and then delete the tables in the source database. You can then backup and drop the Archive database saving the .bak file somewhere cheaper.

The script below will allow you to do just that. It prints the T-Sql to do the job, it doesn’t carry out the job, so it’s completely safe to execute and review.

To use the script below create a target database.

Use the target database name for the variable value @TargetDb

Use the source database name for the variable value @SourceDb

The @KeyWord variable is used to gather all the tables that contain the string of choice, in the example below _DELETE_.

The @RemoveKeyWord variable is a flag that will remove the keyword string from the target database table name, e.g. _DELETE_Sales will become Sales.

IF OBJECT_ID('tempdb..#Table') IS NOT NULL
	DROP TABLE #Table
GO

DECLARE @RemoveKeyWord BIT
DECLARE @Id AS INT
DECLARE @KeyWord AS VARCHAR(256)
DECLARE @SourceDb AS SYSNAME
DECLARE @TargetDb AS SYSNAME
DECLARE @TableName AS SYSNAME
DECLARE @SchemaName AS SYSNAME
DECLARE @Sql AS VARCHAR(MAX)

SET @RemoveKeyWord = 1
SET @KeyWord = '_DELETE_'
SET @TargetDb = 'Archive'
SET @SourceDb = 'Source'
SET NOCOUNT ON

CREATE TABLE #Table (
	Id_Table INT IDENTITY(1, 1)
	,SchemaName SYSNAME
	,TableName SYSNAME
	);

SET @Sql = '
INSERT INTO #Table (
	SchemaName
	,TableName
	)
SELECT s.NAME
	,so.NAME
FROM ' + QUOTENAME(@SourceDb) + '.sys.tables AS so
LEFT JOIN ' + QUOTENAME(@SourceDb) + '.sys.schemas AS s ON so.schema_id = s.schema_id
WHERE so.NAME LIKE ' + '''' + '%' + @KeyWord + '%' + '''' + '
ORDER BY s.NAME ASC'

EXEC (@Sql)

SET @SchemaName = ''

WHILE @SchemaName IS NOT NULL
BEGIN
	SET @SchemaName = (
			SELECT MIN(SchemaName)
			FROM #Table
			WHERE SchemaName > @SchemaName
				AND SchemaName <> 'dbo'
			)

	PRINT 'USE ' + QUOTENAME(@TargetDb) + ';
GO
	
IF NOT EXISTS (SELECT * FROM ' + QUOTENAME(@TargetDb) + '.sys.schemas WHERE name = ' + '''' + @SchemaName + '''' + ')
  BEGIN
    EXEC (' + '''' + 'CREATE SCHEMA ' + QUOTENAME(@SchemaName) + ';' + '''' + ');
  END;
  
'
END

SET @Id = 1

WHILE @Id IS NOT NULL
BEGIN
	SELECT @TableName = TableName
		,@SchemaName = SchemaName
	FROM #Table
	WHERE Id_Table = @Id

	IF @RemoveKeyWord = 1
	BEGIN
		PRINT '
SELECT *
INTO ' + QUOTENAME(@TargetDb) + '.' + QUOTENAME(@SchemaName) + '.' + QUOTENAME(REPLACE(@TableName, @KeyWord, '')) + ' 
FROM ' + QUOTENAME(@SourceDb) + '.' + QUOTENAME(@SchemaName) + '.' + QUOTENAME(@TableName)
	END
	ELSE
	BEGIN
		PRINT '
SELECT *
INTO ' + QUOTENAME(@TargetDb) + '.' + QUOTENAME(@SchemaName) + '.' + QUOTENAME(@TableName) + ' 
FROM ' + QUOTENAME(@SourceDb) + '.' + QUOTENAME(@SchemaName) + '.' + QUOTENAME(@TableName)
	END

	SET @Id = (
			SELECT MIN(Id_Table)
			FROM #Table
			WHERE Id_Table > @Id
			)
END