I've known about the INFORMATION_SCHEMA views (or
system tables) in SQL Server for a while, but I just leared
recently that they are actually part of the SQL-92 standard and
supported on other database platforms.
The INFORMATION_SCHEMA views provide meta data
information about the tables, columns, and other parts of your
database. Because the structure of these tables are standardized
you can write SQL statements that work on various database
platforms.
For example suppose you want to return a resultset with a list of
all columns in a table called employees
SELECT table_name, column_name, is_nullable, data_type, character_maximum_length FROM INFORMATION_SCHEMA.Columns WHERE table_name = 'employees'
Quite a handy feature, but it's hard to find what versions the of various database platforms started supporting this feature, here's a quick list:
- Microsoft …