How to Select Definition of Table Column in SQL Server

As a database professional working with SQL Server, understanding the structure of your tables is crucial. Knowing how to quickly access the definition of table columns is a fundamental skill for database administration, development, and troubleshooting. This article explores various methods to efficiently select and view the definition of table columns within SQL Server, ensuring you have the necessary information at your fingertips.

Utilizing SQL Server Management Studio (SSMS) to View Column Definitions

SQL Server Management Studio (SSMS) offers a user-friendly graphical interface to explore database objects. Here are two primary ways to view table column definitions using SSMS:

Displaying Properties in the Properties Window

The Properties window in SSMS provides a detailed view of a selected object’s attributes. To use this method for viewing table column definitions:

1. Locate your table: In Object Explorer, navigate through your database to find the specific table you are interested in.

2. Open Properties: Right-click on the table name. From the context menu, select Properties.

3. Navigate to Columns: In the Table Properties dialog, select the Columns page from the left-hand menu.

   This will display a grid detailing each column within the table, including its name, data type, length, nullability, and other relevant properties. This is a visually intuitive way to quickly grasp the definition of table columns.

Generating CREATE TABLE Script

For a more comprehensive definition, including indexes, constraints, and other table-level settings, generating the CREATE TABLE script is beneficial. This script essentially contains the complete definition of the table, including all column specifications.

1. Locate your table: As before, find your target table in Object Explorer.

2. Script Table As: Right-click on the table, go to Script Table as, then CREATE To, and finally select either New Query Editor Window, Clipboard, or File depending on where you want to output the script.

   This action will generate a T-SQL script that, if executed, would recreate the table. Within this script, you will find the detailed definition of each column, including data types, constraints (like NOT NULL, PRIMARY KEY, FOREIGN KEY), and default values.

Using Transact-SQL (T-SQL) to Select Column Definitions

For those who prefer or require a programmatic approach, Transact-SQL (T-SQL) offers powerful methods to query and retrieve table column definitions.

Employing the sp_help Stored Procedure

The sp_help system stored procedure is a versatile tool for retrieving information about database objects. To view column definitions using sp_help:

1. Open a New Query Window: In SSMS, click New Query to open a query editor.

2. Execute sp_help: Type and execute the following T-SQL command, replacing 'dbo.yourTableName' with the actual schema and table name you are interested in:

   EXEC sp_help 'dbo.yourTableName';

   This procedure returns multiple result sets, one of which provides detailed information about each column in the specified table. This includes column name, data type, length, computed status, identity properties, and more.

Querying System Catalog Views Directly

System catalog views provide a programmatic interface to SQL Server’s metadata. For granular control and customized queries, you can directly query system catalog views to retrieve column definitions. The sys.columns, sys.tables, and sys.schemas views are particularly useful for this purpose.

Here is an example T-SQL query to select column definitions:

SELECT
    s.name AS schema_name,
    t.name AS table_name,
    c.name AS column_name,
    TYPE_NAME(c.user_type_id) AS data_type,
    c.max_length,
    c.is_nullable,
    c.is_identity,
    -- Add other relevant column properties as needed
    c.* -- Include all columns for full details
FROM sys.columns AS c
INNER JOIN sys.tables AS t
    ON t.object_id = c.object_id
INNER JOIN sys.schemas AS s
    ON s.schema_id = t.schema_id
WHERE t.name = 'yourTableName' AND s.name = 'dbo' -- Replace with your table and schema
ORDER BY c.column_id;

This query joins these system views to retrieve schema name, table name, and detailed column properties like column name, data type, maximum length, nullability, and identity status. You can customize this query to select specific columns from sys.columns that are most relevant to your needs.

Conclusion

Understanding table column definitions is essential for anyone working with SQL Server databases. Whether you prefer the visual interface of SSMS or the programmatic power of T-SQL, SQL Server provides multiple methods to efficiently access this critical information. By mastering these techniques, you can effectively manage, develop, and troubleshoot your SQL Server databases.