====== Transaction ======
[[https://learn.microsoft.com/en-us/sql/t-sql/language-elements/transactions-transact-sql?view=sql-server-ver16|T-SQL Transactions]]

A transaction is a single unit of work. If a transaction is successful, all of the data modifications made during the transaction are committed and become a permanent part of the database. If a transaction encounters errors and must be canceled or rolled back, then all of the data modifications are erased.

<WRAP center round danger 60%>
Tables are locked while transactions are active. When using explicit transactions; begins should always be followed by a commit or rollback to ensure the table is unlocked.
</WRAP>


===== Begin Transaction =====
Marks the starting point of an explicit, local transaction. Explicit transactions start with the BEGIN TRANSACTION statement and end with the COMMIT or ROLLBACK statement.
<code sql>
BEGIN TRANSACTION
</code>

===== Rollback Transaction =====
Rolls back an explicit or implicit transaction to the beginning of the transaction, or to a savepoint inside the transaction. You can use ROLLBACK TRANSACTION to erase all data modifications made from the start of the transaction or to a savepoint. It also frees resources held by the transaction.
This does not include changes made to local variables or table variables. These are not erased by this statement.
<code sql>
ROLLBACK TRANSACTION
</code>

===== Commit Transaction =====
Marks the end of a successful implicit or explicit transaction. If @@TRANCOUNT is 1, COMMIT TRANSACTION makes all data modifications since the start of the transaction a permanent part of the database, frees the transaction's resources, and decrements @@TRANCOUNT to 0. When @@TRANCOUNT is greater than 1, COMMIT TRANSACTION decrements @@TRANCOUNT only by 1 and the transaction stays active.
<code sql>
COMMIT TRANSACTION
</code>