Key Categories of Data Types

• Integer Types

  • Represent positive and negative whole numbers.

• Decimal Types

  • Represent numbers with fractional values.

• Character Types

  • Represent textual data (e.g., letters, words).

• Time Types

  • Represent date and time values or both.

• Binary Types

  • Store data exactly as it appears in memory or files, bit for bit.

• Semantic Types

  • Based on other types, with additional special meanings.

• Simple Data Types

  • Have simple internal structures and are easy to understand.

Complex Data Types

• Spatial Types

  • Store geometric information such as lines, polygons, and map coordinates.

• Composite Types

  • Support collections of different values, usually organized in sets or arrays.

• Document Types

  • Contain textual data in a structured format, for example, XML or JSON.

• Object Types

  • Enable object-oriented programming capabilities (e.g., methods, subclasses).

User-Defined Types

• System-Defined Types

  • Built-in types provided by the database systems (e.g., FLOAT, CHAR, ENUM, SET).

• User-Defined Types

  • Created by database designers to meet specific application needs using the CREATE TYPE statement.

  • Example statements:

    • CREATE TYPE Size AS ENUM ('Small', 'Medium', 'Large', 'XLarge');

    • Used in tables as:

      CREATE TABLE Clothing (
          ItemNumber INTEGER,
          ItemName VARCHAR(20),
          ItemSize Size
      );
      INSERT INTO Clothing VALUES (3281, 'Sahara sun bonnet', 'Small');
      INSERT INTO Clothing VALUES (3400, 'Zephyr shorts', 'XLarge');

Important Points about CREATE TYPE

• CREATE TYPE allows for defining new types based on existing system-defined types.

• User-defined types can be used in table definitions.

Quiz Questions Review

1. Which database does not support the CREATE TYPE statement?

   • Answer: MySQL

2. User-defined types can be:

   • Answer: Either simple or complex types.

3. System-defined types can be:

   • Answer: Either simple or complex types.

Examples of System-Defined Types

• Simple Types: INTEGER, DECIMAL

• Complex Types: JSON, XML