Data Types

Owned by Computer Science Department
Aug 01, 2023
2 min read

SQL (Structured Query Language) data types define the type of data that can be stored in a database table column. Each column in a table is associated with a specific data type, which determines the kind of data it can hold and the operations that can be performed on that data. SQL provides a wide range of data types to accommodate various types of information.

 

Here are some common SQL data types:

  1. Numeric Data Types:

    • INTEGER: A whole number, typically representing signed 32-bit values.

    • SMALLINT: A small whole number, typically representing signed 16-bit values.

    • DECIMAL (also known as NUMERIC): A fixed-point number with a specified precision and scale.

    • FLOAT: A floating-point number, representing approximate numeric values with a variable number of significant digits.

    • DOUBLE (also known as DOUBLE PRECISION): A double-precision floating-point number, representing a higher precision than FLOAT.

  2. Character Data Types:

    • CHAR: A fixed-length character string with a specified length.

    • VARCHAR: A variable-length character string with a maximum length.

    • TEXT: A large character string with a varying length, suitable for storing large amounts of text.

  3. Date and Time Data Types:

    • DATE: A date value in the format YYYY-MM-DD.

    • TIME: A time value in the format HH:MM:SS.

    • TIMESTAMP: A combination of date and time in the format YYYY-MM-DD HH:MM:SS.

    • DATETIME: Similar to TIMESTAMP, representing a date and time value.

  4. Boolean Data Type:

    • BOOLEAN (or BOOL): A data type representing true or false values.

  5. Binary Data Types:

    • BLOB (Binary Large Object): Used to store large binary data like images or files.

    • BINARY: A fixed-length binary string with a specified length.

    • VARBINARY: A variable-length binary string with a maximum length.

  6. Enumerated Data Type:

    • ENUM: A user-defined data type that restricts the column to a set of predefined values.

  7. JSON Data Type:

    • JSON: Used to store JSON (JavaScript Object Notation) data.

These are just a few examples of SQL data types. Different database management systems may have additional data types or variations, but the concepts and principles remain similar. When creating database tables, it's essential to choose the appropriate data types that best match the nature of the data being stored to ensure data integrity and efficient storage and retrieval of information.