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Database Dictionary (1-1) --- Server, Database, Schema, Table and Column

Note: this article is published on 09/23/2024.

This series of articles will discuss Database Dictionary related issues

Introduction:

In this article, we will discuss the basic elements of database schema: Server, Database, Schema, Table and Column. We will discuss how to retrieve those infor from SQL Server.

  • A - Introduction
  • B - Data Source
  • C - Retrieve Schema Info by SQL in SQL Server
    • Get Servers (including linnked servers and remote servers) by SQL
    • Get Databases by SQL
    • Get Schemata by SQL
    • Get Tables by SQL
    • Get Columns by SQL

 B - Data Source

Database data stored in system database:

The Resource database is a read-only database that contains all the system objects that are included with SQL Server. SQL Server system objects, such as sys.objects, are physically persisted in the Resource database, but they logically appear in the sys schema of every database. The Resource database does not contain user data or user metadata.

The Resource database makes upgrading to a new version of SQL Server an easier and faster procedure. In earlier versions of SQL Server, upgrading required dropping and creating system objects. Because the Resource database file contains all system objects, an upgrade is now accomplished simply by copying the single Resource database file to the local server.

Resource database location:

Resource Version:

Resource Last Update Date Time:

 C - Retrieve Schema Info by SQL in SQL Server

Retrieve info from SQL server for:

  • Server
  • Database
  • Schema
  • Table
  • Column

Get Servers (including linnked servers and remote servers) by SQL

SELECT * FROM sys.servers

SELECT * FROM sysservers

SELECT * FROM sys.sysservers

Contains a row per linked or remote server registered, and a row for the local server that has server_id = 0. Such as

and

Get Databases by SQL

SELECT * FROM sys.databases

SELECT * FROM sys.sysdatabases

Contains one row per database in the instance of SQL Server.

and

Note:

Besids getting database Servers and databases, all other sys.command are running within a database:

Get Schemata by SQL

SELECT * FROM sys.schemas

SELECT COUNT(*) FROM sys.schemas

SELECT * FROM INFORMATION_SCHEMA.SCHEMATA

SELECT COUNT(*) FROM INFORMATION_SCHEMA.SCHEMATA

SELECT *
FROM INFORMATION_SCHEMA.SCHEMATA
WHERE SCHEMA_NAME IN (
						SELECT DISTINCT TABLE_SCHEMA
						FROM INFORMATION_SCHEMA.TABLES
					)

SELECT * FROM sys.schemas
WHERE name IN (
				SELECT TABLE_SCHEMA
				FROM INFORMATION_SCHEMA.TABLES
			   )

Such as

and

Get Tables by SQL

SELECT table_name
FROM INFORMATION_SCHEMA.TABLES

SELECT name
FROM sys.tables

SELECT name
FROM sysobjects
WHERE xtype = 'U'

SELECT name
FROM sys.objects
WHERE type_desc = 'USER_TABLE'

such as

and

and

and

and

Get Columns by SQL

SELECT * FROM sys.columns

SELECT * FROM sys.all_columns

SELECT * FROM INFORMATION_SCHEMA.COLUMNS

such as

and

 

References:


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