How Can I Retrieve Table and Field Metadata in SQL Server?

Obtaining Table and Field Metadata in a Database

In the realm of database management, accessing information about the structure of a database is crucial for various tasks. For instance, if you're developing an Object-Relational Mapping (ORM) tool, you'll need to retrieve the list of tables and their corresponding fields.

Methodologies for Retrieving Metadata

To accomplish this task, SQL Server offers two main methodologies:

1. Using Object Catalog Views:

This approach involves querying the following system table views:

• sys.objects: Provides information about the tables in the database.
• sys.columns: Contains details about the columns (fields) in each table.
• sys.types: Describes the data types used in the columns.

By joining these views, you can obtain comprehensive information about tables and their fields.

2. Using Information Schema Views:

An alternative method is to use Information Schema views, which provide a standardized mechanism for accessing database metadata:

• INFORMATION_SCHEMA.TABLES: Lists the tables in the database.
• INFORMATION_SCHEMA.COLUMNS: Contains information about the columns in each table.

Sample Query

Here's an example query using the Object Catalog View approach:

SELECT T.name AS Table_Name,
       C.name AS Column_Name,
       P.name AS Data_Type,
       C.max_length AS Size,
       CAST(P.precision AS VARCHAR) + '/' + CAST(P.scale AS VARCHAR) AS Precision_Scale
FROM sys.objects AS T
JOIN sys.columns AS C ON T.object_id = C.object_id
JOIN sys.types AS P ON C.system_type_id = P.system_type_id
WHERE T.type_desc = 'USER_TABLE';

This query will return a result set containing the list of tables and their associated fields.

Useful SQL Server Blogs

For further exploration of SQL Server-related topics, consider the following blogs:

• [DBALink](http://dbalink.wordpress.com/)
• [SQL Server Central](https://www.sqlservercentral.com/)
• [Brent Ozar Unlimited](https://www.brentozar.com/)

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