Commit
The command used to permanently save a transaction into the database is 'Commit'. When a transaction is executed in a database management system (DBMS), it may involve multiple operations such as inserting, updating, or deleting data. These operations are grouped together as a single unit called a transaction. The purpose of a transaction is to maintain the consistency and integrity of the database.

Explanation:
When a transaction is executed, the changes made to the database are temporarily stored in a transaction log. This log records all the modifications made during the transaction. However, these changes are not immediately applied to the actual database. The 'Commit' command is used to permanently save these changes and make them visible to other users accessing the database.

Importance of Commit:
Committing a transaction is important for several reasons:

1. Data Consistency: By committing a transaction, the changes made to the database are finalized and all related data is updated accordingly. This ensures that the database remains consistent and avoids any conflicting or incorrect information.

2. Data Integrity: Committing a transaction ensures that the changes made are durable and will persist even in the event of a system failure or power outage. It guarantees that the database will be in a consistent state after recovery.

3. Concurrency Control: In a multi-user environment, multiple transactions can be executed concurrently. The 'Commit' command allows one transaction to complete its execution and release any locks it holds on the data, allowing other transactions to access the modified data.

4. Rollback Prevention: Once a transaction is committed, it cannot be rolled back unless a new transaction is executed to undo the changes. Committing a transaction ensures that the changes are permanent and cannot be easily reversed, providing data integrity.

Conclusion:
The 'Commit' command is used to permanently save a transaction into the database, ensuring data consistency, integrity, and durability. It is a crucial step in the transaction process and plays a vital role in maintaining a reliable and accurate database.