SQL Server: should I use information_schema tables over sys tables?

sql sql-server sql-server-2008 stored-procedures metadata
juur picture juur · Sep 6, 2010 · Viewed 25.7k times · Source

In SQL Server there is two schemas for metadata:

  • INFORMATION_SCHEMA
  • SYS

I have heard that INFORMATION_SCHEMA tables are based on ANSI standard. When developing e.g. stored procedures, should it be wise to use INFORMATION_SCHEMA tables over sys tables?

Answer

Martin Smith picture Martin Smith · Sep 6, 2010

Unless you are writing an application which you know for a fact will need to be portable or you only want quite basic information I would just default to using the proprietary SQL Server system views to begin with.

The Information_Schema views only show objects that are compatible with the SQL-92 standard. This means there is no information schema view for even quite basic constructs such as indexes (These are not defined in the standard and are left as implementation details.) Let alone any SQL Server proprietary features.

Additionally it is not quite the panacea for portability that one may assume. Implementations do still differ between systems. Oracle does not implement it "out of the box" at all and the MySql docs say:

Users of SQL Server 2000 (which also follows the standard) may notice a strong similarity. However, MySQL has omitted many columns that are not relevant for our implementation, and added columns that are MySQL-specific. One such column is the ENGINE column in the INFORMATION_SCHEMA.TABLES table.

Even for bread and butter SQL constructs such as foreign key constraints the Information_Schema views can be dramatically less efficient to work with than the sys. views as they do not expose object ids that would allow efficient querying.

e.g. See the question SQL query slow-down from 1 second to 11 minutes - why? and execution plans.

INFORMATION_SCHEMA

Plan

sys

Plan

Related questions

SQL Server Insert if not exists

I want to insert data into my table, but insert only data that doesn't already exist in my database. Here is my code: ALTER PROCEDURE [dbo].[EmailsRecebidosInsert] (@_DE nvarchar(50), @_ASSUNTO nvarchar(50), @_DATA nvarchar(30) ) AS BEGIN INSERT INTO EmailsRecebidos (De, Assunto, …

Read More
SQL Server: Invalid Column Name

I am working on modifying the existing SQL Server Stored Procedure. I added two new columns to the table and modified the stored procedure as well to select these two columns as well. Although the columns are available in the …

Read More
Stored procedure EXEC vs sp_executesql difference?

I've written two stored procedure one with sp_executesql and other doesn't have sp_executesql both are executing properly same results, I didn't get what is the difference here between EXEC (@SQL) vs EXEC sp_executesql @SQL, N'@eStatus varchar(12)…

Read More