Creating Tables in SQL Server: Column Definitions Explained

Common SQL Server Data Types

Choosing the right data type is crucial for performance and storage.

SQL Server supports various data types for numbers, text, dates, and more.

• INT: Integer numbers.
• VARCHAR(n): Variable-length string up to n characters.
• DATETIME: Date and time values.
• DECIMAL(p,s): Fixed precision and scale numbers.

Applying Constraints to Columns

Constraints enforce rules on the data stored in columns.

They help maintain data integrity and prevent invalid data entry.

• NOT NULL: Column must have a value.
• PRIMARY KEY: Uniquely identifies each row.
• UNIQUE: Ensures all values are distinct.
• DEFAULT: Provides a default value if none is specified.

Example: Creating a Table with Column Definitions

Here is an example of creating a table with various column definitions and constraints.