Which DDL command is not used to modify the data type of a column in a table?a.ALTER COLUMNb.MODIFY COLUMNc.CHANGE COLUMNd.UPDATE COLUMN

Break Down the Problem

1. Identify the purpose of the DDL command in modifying column data types in a database table.
2. Examine each option for its applicability in altering a column's data type.

Relevant Concepts

• DDL (Data Definition Language) commands are used to define and modify database structures.
• The commands typically involved in modifying a column's data type are ALTER COLUMN, MODIFY COLUMN, and CHANGE COLUMN.
• Understanding which command does not belong to this category is crucial.

Analysis and Detail

1. ALTER COLUMN: This command is commonly used to change the structure of an existing column in a table, including its data type.
2. MODIFY COLUMN: This command is typically used in some SQL dialects (like MySQL) to change the definition of an existing column, including its data type.
3. CHANGE COLUMN: This command is also used in some SQL DBMSs (like MySQL) for altering column definitions, including renaming a column and changing its data type.
4. UPDATE COLUMN: This is not a standard DDL command. The purpose of the UPDATE command is to change data in the table, not its structure or definition.

Verify and Summarize

• The commands that actually modify the data types of a column are ALTER COLUMN, MODIFY COLUMN, and CHANGE COLUMN.
• The command UPDATE COLUMN does not exist in SQL's DDL context and is therefore not related to changing the data structure.

Final Answer

The DDL command that is not used to modify the data type of a column in a table is d. UPDATE COLUMN.