Server Side Guy

Recently I needed to create a duplicate of PGSQL database.  Being a MySQL guy, I didn’t know off hand how to do it, but here is an easy way:

pg_dump original_db > original_db.sql
createdb new_db
psql -d new_db < original_db.sql

From a bird’s eye view, you are creating a dump of the original database and outputting it to a file. From there, make sure the new database is created and use your dump file as input for that database. It wouldn’t be too hard to make this into a one-liner, but I like to see intermediate steps to make sure things are going well.

I ran accross the SQL Server error 3154. In SQL Server 2008, it says “Restore Failed for Server ‘ServerName\InstanceName’” Additional Information: “System.Data.SQLClient.SqlError: The backup set holds a backup of a database other than the existing ‘dbname’ database. (Microsoft.SqlServer.Smo)”

Solution:

Use WITH REPLACE.  This can be found in the GUI tool or done in T-SQL as follows:

RESTORE DATABASE dbname
FROM DISK = 'C:\dbname.bak'
WITH REPLACE

Escaping single quotes (‘) in Transact-SQL is done by replacing the single quote with two single quotes. So:

SELECT 'I went to Kinko''s'

Returns “I went to Kinko’s”

The only case where two consecutive single quotes don’t return a single quote is when the first one also starts the string.  In this case, if only two single quotes are present, the second one ends the string and the return value is the empty string.  SQL Blog Casts has a good example of this.

Doing the same in MySQL

Escaping a single quote in MySQL is done by adding a backslash before it (\’)

SELECT 'I went to Kinko\'s'