What is the Difference Between Update and Alter?
🆚 Go to Comparative Table 🆚The main difference between the UPDATE and ALTER commands in SQL lies in their purposes and what they modify. Here are the key differences:
ALTER Command:
- It is a Data Definition Language (DDL) statement.
- It operates on the structure level, not the data level.
- It is used to add, delete, or modify the attributes of the tables in a database, such as adding or dropping columns.
- By default, it initializes the values of all tuples as NULL.
UPDATE Command:
- It is a Data Manipulation Language (DML) statement.
- It operates on the data level.
- It is used to update existing records in a database, modifying the values of the records in the relations.
- It sets specified values in a tuple using the UPDATE command.
In summary, the ALTER command is used to modify the structure of a table, while the UPDATE command is used to modify the data within the table.
Comparative Table: Update vs Alter
The main difference between the UPDATE
and ALTER
commands in SQL lies in their function: ALTER
is used to modify the structure of a table, while UPDATE
is used to modify the data within the table. Here is a comparison table highlighting their differences:
Feature | ALTER Command | UPDATE Command |
---|---|---|
Purpose | Modify table structure (add, delete, modify columns) | Modify data within existing columns |
Type | Data Definition Language (DDL) | Data Manipulation Language (DML) |
Function | Operates on the structure level | Operates on the data level |
Usage | Add, remove, or change table attributes | Update the data in the table |
For example, the ALTER
command can be used to add a new column to a table, while the UPDATE
command can be used to modify the values within that new column for specific rows.
Read more:
- Insert vs Update vs Alter
- Update vs Upgrade
- Modify vs Change
- Deferred Update vs Immediate Update
- Delete vs Drop
- Change vs Transformation
- DDL vs DML
- Delete vs Truncate
- Drop vs Truncate
- Modification vs Revision
- Amend vs Emend
- Addendum vs Amendment
- Change vs Development
- Alternate vs Alternative
- Change vs Innovation
- Primary key vs Unique key
- Take vs Get
- Revision vs Editing
- Difference vs Different