Double Dot table qualifier

Question

I am looking at a new database schema developed by an external vendor. There are two databases:

Database1
Database2

They have sent me an S

Answer 1

This is a database schema. Full three-part name of a table is:

databasename.schemaname.tablename

For a default schema of the user, you can also omit the schema name:

databasename..tablename

You can also specify a linked server name:

servername.databasename.schemaname.tablename

You can read more about using identifiers as table names on MSDN

Answer 2

Thanks to this dot, the default schema (dbo) is choosen for your query.

When you have two databases it is required to give the full path to the table. If we have: Database1 schema: dbo, guest table dbo.A, guest: A Database2 schema: dbo, guest table dbo.B, guest: B

if we create select statement like:

select * from Database2..B

We are selecting data from dbo.B table IF we would like to specify schema we need to refer as

select * from Database2.schemaname.tablename

EDIT: As colleagues pointed out, the default schema can be changed in database, however in this particular example it seems to be dbo :)