SQL COMMIT Statement

Use the BEGIN WORK statement to initiate a transaction, which is a set of database activities that are terminated by the COMMIT WORK or ROLLBACK WORK statements and treated as a single unit of work by the database server. The ANSI/ISO standard for SQL has been extended with this statement.

The START TRANSACTION or BEGIN statement starts a new transaction, making it explicit and locking the database until it is committed or rolled back. COMMIT saves the current transaction's alterations and makes them permanent. ROLLBACK cancels the changes made by the current transaction.

For the current session, the SET autocommit statement disables or allows the default autocommit mechanism.

START TRANSACTION and SET autocommit = 1 commit the current transaction, if any, automatically.

COMMIT and ROLLBACK, as well as the CHAIN and RELEASE clauses, allow the optional WORK keyword. Additional transaction control can be achieved by using CHAIN and RELEASE. The default ending behaviour is determined by the value of the completion type system variable.

Syntax:

START TRANSACTION [transaction_property [, transaction_property] ...] | BEGIN [WORK]
COMMIT [WORK] [AND [NO] CHAIN] [[NO] RELEASE]
ROLLBACK [WORK] [AND [NO] CHAIN] [[NO] RELEASE]
SET autocommit = {0 | 1}

transaction_property:
    WITH CONSISTENT SNAPSHOT
  | READ WRITE
  | READ ONLY

Example 1:

START TRANSACTION;
SELECT @A:=SUM(salary) FROM table1 WHERE type=1;
UPDATE table2 SET summary=@A WHERE type=1;
COMMIT;

Example 2: BEGIN TRAN new name WITH MARK can be nested inside a non-marked transaction.

As a result, regardless of the name supplied to the transaction previously, new name becomes the mark name. The mark's name is M2 in the given description.

BEGIN TRAN T1;  
UPDATE table1 ...;  
BEGIN TRAN M2 WITH MARK;  
UPDATE table2 ...;  
SELECT * from table1;  
COMMIT TRAN M2;  
UPDATE table3 ...;  
COMMIT TRAN T1;  

When nesting transactions, trying to mark a transaction that is already marked results in a warning (not error) message:

A COMMIT command in SQL is a transaction command that saves all modifications required by a specific transaction in a relational database management system since the last COMMIT or ROLLBACK command.

It marks the completion of a successful transaction. The COMMIT statement is used to complete a transaction in an application. All modifications made to the database by the transaction are rendered permanent when a COMMIT statement is executed. It indicates that after you commit a transaction, you can't undo it because a valid COMMIT process releases all transaction capabilities.

As a result, a database developer's primary obligation should be to only execute a COMMIT action when it is sequentially and logically accurate; else, he or she risks losing the database's major relationships.

Adjustments introduced by one transaction may not be visible to other transactions until the transaction is committed, depending on the transaction's isolation level. The default behavior of OpenEdge SQL is to make database updates visible only once the transaction is committed.

Syntax:

The basic syntax for using a COMMIT command in SQL SERVER is as follows :

BEGIN TRANSACTION;
{a set of SQL statements};
COMMIT TRANSACTION;

For other relational databases, such as MYSQL, a reduced form of syntax is as follows :

{a set of SQL statements};
COMMIT;

parameters:

The parameters used in the above syntax are:

1. BEGIN TRANSACTION: This signals the start of the transaction's operations or updates.

2. a sequence of SQL statements: This is where you describe the activity that has to be completed.

3. COMMIT: COMMIT is a SQL transaction statement that saves the adjustments done by the SQL statements in the preceding example to the database forever.

Note: The COMMIT statement has no effect on the contents of the host variables or the program's control flow.

Example 1:

Begin Tran T1
Update Tbl_Emp Set Job_Title='Market Analyst' Where Emp_Id=123
Commit Tran T1

Example 2: This programme shows how to perform the COMMIT command on a DELETE statement.

BEGIN TRANSACTION;
DELETE FROM employees
WHERE employeeid = 10022;
COMMIT TRANSACTION;

Example 3: Consider the CUSTOMERS table having the following records :

The instance below will delete all records in the table over the age of 27 and then COMMIT the changes to the database.

DELETE FROM CUSTOMERS WHERE AGE = 27;

COMMIT;

As a result, two rows from the table will be removed, and the SELECT operation will get the following result.

java.sql.Statement is used for batch processing. You can use the statement to implement many DML statements (update, insert, delete) at the same time.

This is accomplished by constructing a single statement object, appending the statements to run, and then running the batch as a whole.

Committing within a loop is one of the issues with poorly coded pl/sql batch processing. This is usually done with the idea that if the program aborts in the middle of processing, it can resume from the point of failure.

Syntax:

The basic algorithm for this type of processing is like this:

Begin
Loop
Do some processing
Do some DML (insert/update/delete)
Commit
End loop
End

Example:

Connection connection = ...; // obtained earlier
connection.setAutoCommit(false); // disabling autocommit is recommended for batch execution

try (Statement statement = connection.createStatement()) {
    statement.addBatch("INSERT INTO users (id, username) VALUES (2, 'anna')");
    statement.addBatch("INSERT INTO userrole(userid, rolename) VALUES (2, 'admin')");
    
    statement.executeBatch();//executing the batch 
}

connection.commit();//commit statements to apply changes 

Note: statement.executeBatch(); will return int[] to hold returned values, you can execute your batch like this :

int[] stmExc = statement.executeBatch();//executing the batch 

Commit is used to make long-term alterations. When we use Commit in a query, the changes that it makes are permanent and visible. We are unable to rollback once you have used Commit.

Syntax :

begin tran tranName
Command for operation
commit tran tranName

The name of the transaction is tranName, and the command for operation is the SQL statement that is used to perform the operation, such as changing or inserting data.

Example 1:

begin tran a  
update emp set employeeName ='A' where employeeid=11  
commit tran a

Here a is the name of the transactions and we update employeeName a to in the table emploee on the basis of employeeId. The change made by this command will be permanent and we could not Rollback after the commit command.

Example 2: do we need to specify commit to save changes in mysql:

BEGIN;
SELECT @A:=SUM(salary) FROM table1 WHERE type=1;
UPDATE table2 SET summmary=@A WHERE type=1;
COMMIT;

Every time enclose your DELETE command in a BEGIN TRAN - COMMIT code block when deleting data from a database. You can execute the BEGIN TRAN and your DELETE using the technique given below, then verify how many records were affected before committing your updates.

Example 1: use of COMMIT command on a DELETE statement:

BEGIN TRANSACTION;
DELETE FROM employees
WHERE employeeid = 10022;
COMMIT TRANSACTION;

Example 2: The following example deletes a job candidate. It uses AdventureWorks.

BEGIN TRANSACTION;   
DELETE FROM HumanResources.JobCandidate  
    WHERE JobCandidateID = 13;   
COMMIT TRANSACTION; 

Example 3: I've commented out the COMMIT component of my script, like I did in the previous approach, so it doesn't get executed by mistake.

BEGIN TRAN
DELETE FROM Main WHERE col1 IN (SELECT col1 From ToDelete);
--ROLLBACK TRAN
--COMMIT TRAN

DELETE output

As in the preceding example, if I see that too many rows have been deleted, I can undo the transaction and change the script as follows. In this example, it returned the proper value, allowing me to execute my commit statement.

Example 4:

EXEC SQL DELETE FROM foo WHERE number = 9999;
EXEC SQL COMMIT;

If you merely use INSERT, the records you insert will be committed by default, and you won't be able to roll them back.

The insert commits values after you cancel the proc call, and the modifications performed by the insert are still committed if you terminate the proc call after the insert. (It's the equivalent of wrapping each statement between BEGIN and COMMIT.)

Example 1: This would not be the case if you did something like this:

begin tran
insert into table values(...)
exec proc
commit tran

If you abort the proc call, the insert will be rolled back as well. This is a basic test that you can confirm with your own code.

Example 2: use of COMMIT command on an INSERT statement.

BEGIN TRANSACTION;
INSERT INTO employees(employeeid,lastname,firstname,gender,salary,city,create_at)
VALUES(10030,'Woods','Charles','Male','14567','New Delhi','2005-12-31');
COMMIT TRANSACTION;

Example 3:

BEGIN TRANSACTION
   insert into employee values(11111, 'Ann', 'Smith','d2')
   insert into employee values(22222, 'Matthew', 'Jones','d4')
   insert into employee values(33333, 'John', 'Barrimore', 'd2')
   COMMIT TRANSACTION
   GO

FETCH DATA:

select * from employee
 GO

Output:

We utilized the XACT_STATE() function in our stored procedure to verify the transaction's state before performing a COMMIT TRANSACTION or ROLLBACK TRANSACTION within the CATCH block.

Example 1: Develop a new stored procedure that deletes a row from the sales.persons table:

CREATE PROC usp_delete_person(
    @person_id INT
) AS
BEGIN
 BEGIN TRY
 BEGIN TRANSACTION;
        
 -- delete the person
 DELETE FROM sales.persons 
 WHERE person_id = @person_id;
 
 -- if DELETE succeeds, commit the transaction
 COMMIT TRANSACTION;  
 END TRY
 BEGIN CATCH
  
 -- report exception
 EXEC usp_report_error;
        
 -- Test if the transaction is uncommittable.  
 IF (XACT_STATE()) = -1  
 BEGIN  
   PRINT  N'The transaction is in an uncommittable state.' +  
    'Rolling back transaction.'  
 ROLLBACK TRANSACTION;  
 END;  
        
 -- Test if the transaction is committable.  
 IF (XACT_STATE()) = 1  
 BEGIN  
  PRINT N'The transaction is committable.' +  
   'Committing transaction.'  
 COMMIT TRANSACTION;     
END;  
END CATCH
END;
GO

Example 2: My favorite usage of a TRY/CATCH construct is when you are purging data and retrying the DELETE due to a deadlock:

CREATE PROC usp_Table2_Purge (@purgedate datetime, @batch int = 5000)
AS
SET NOCOUNT ON;
 
DECLARE
  @rc int = 1, @retries tinyint = 0, @maxretries tinyint = 10,
  @errormessage nvarchar(4000), @errorseverity int, @errorstate int;
     
WHILE @rc <> 0 AND @retries <= @maxRetries
BEGIN;
 BEGIN TRY;
 BEGIN TRAN;
 
DELETE TOP (@batch) Table2
 FROM Table2
 JOIN Table1
 ON Table2.Table1Id = Table1.Table1Id
 WHERE Table1.CreatedDate < @purgeDate;
    
SELECT @rc = @@ROWCOUNT;
      
IF XACT_STATE() = 1 COMMIT TRANSACTION;
 END TRY
 BEGIN CATCH;
 IF XACT_STATE() <> 0 ROLLBACK TRANSACTION;
    
IF ERROR_NUMBER() = 1205 AND @retries < @maxRetries -- 1205 is the deadlock error
 BEGIN;
 SET @retries = @retries + 1;
 
WAITFOR DELAY '00:00:10'; --pause to hopefully avoid deadlock next batch
END;
ELSE -- some other error or done retrying
 BEGIN;
SELECT  
 @errormessage = ERROR_MESSAGE() 
  + '. Error in line ' 
  + CAST(ERROR_LINE() AS varchar(1000)) 
  + ' of procedure ' + ERROR_PROCEDURE(),
  @errorseverity = ERROR_SEVERITY(),
  @errorstate = ERROR_STATE();
          
RAISERROR (@errormessage, @errorseverity, @errorstate);
 RETURN;
 END;
 END CATCH;
END;
 
RETURN;

A successful implicit or explicit transaction comes to a close with the COMMIT Transaction.

When @@TRANCOUNT is 1, all data updates are committed, the transaction's resources are freed, and @@TRANCOUNT is decremented to 0. COMMIT TRANSACTION only decrements @@TRANCOUNT by 1 when @@TRANCOUNT is more than 1, and the transaction remains active.

The following steps illustrate to create a transaction:

• The BEGIN TRANSACTION command is used to initiate the transaction.
• Then we can choose whether to commit the data or roll it back.
• The COMMIT TRAN statement commits the data changes to the database, making the changes permanent.

Syntax:

COMMIT [ { TRAN | TRANSACTION } [ transaction_name | @transaction_name_variable ] ]
[ WITH ( DELAYED_DURABILITY = { OFF | ON } ) ] ;

Example 1: let’s complete the open transaction with a COMMIT TRAN statement:

BEGIN TRAN
UPDATE Person 
SET    Lastname = 'Lucky', 
        Firstname = 'Luke' 
WHERE  PersonID = 1
SELECT @@TRANCOUNT AS OpenTransactions 
COMMIT TRAN 
SELECT @@TRANCOUNT AS OpenTransactions

Example 2: Below are the commands that explain the COMMIT operations in SQL Server:

-- Start a new transaction    
BEGIN TRANSACTION  

-- SQL Statements  
 INSERT INTO Product VALUES(116, 'Headphone', 2000, 30)  
 UPDATE Product SET Price = 450 WHERE Product_id = 113  
 -- Commit changes   
COMMIT TRANSACTION 

Example 3: Commit transaction example:

USE model;
GO
BEGIN TRANSACTION;
GO
DELETE FROM students WHERE id = 7 and section = 'History';
GO
insert into students(id,first_name, last_name, gender,city, country, section)
values(7,'Ashley','THOMPSON','F','London','Liverpool', 'History');
GO
COMMIT TRANSACTION;
GO

On a UPDATE statement, the COMMIT command is used. Using a select query, we can determine whether the update process was successful or not.

Example 1: I'm attempting to write it manually because the update statement lacks an explicit commit.

Update mytable
set status=0;
Commit;

I am getting message as Commit has no begin transaction

Example 2: Table has a millions of rows and you want to update whole rows in table like below statement

UPDATE TABLE_NAME
SET COLUMN_NAME='XXXXXX';
COMMIT;

It will raise an exception because of limited size of UNDO/ROLLBACK log file.

To solve this problem by code, you can commit after n updates to ignore overloading redo log file.

Example 3:

BEGIN TRANSACTION;
UPDATE employees
SET departmentid = '4002'
WHERE employeeid = 10030
COMMIT TRANSACTION;

Using a select query, determine whether the operation is working in the above instance. The department id has been modified, as can be seen.

A transaction can either be ROLLBACKED or COMMITTED. The BEGIN and END blocks are not transactions and have nothing to do with them.

BEGIN TRAN, COMMIT, and ROLLBACK are commands that start and stop transactions. They do not define a new block of code; instead, they define the transaction boundaries. , and START TRANS COMMIT TRANS creates a transaction out of the enclosing block and, depending on the server settings, will rollback the transaction if an error occurs. , and Code blocks are dealt with by BEGIN and END.

Code blocks are dealt with by BEGIN and END. The usual BEGIN and END are not used for transactions, as they are comparable to the curly brackets seen in many languages. Instead, they serve the same purpose as brackets in C#/C++/Java: denoting that a block of code is a single unit.

Note: Distinct blocks of code for BEGIN TRAN and COMMIT.

There is only a conditional reason to rollback in the event of an exception, timeout, or another general failure; otherwise, there is no cause to rollback.

The syntax I tried to discover information on the distinctions between these statements on the internet, and it appears that they are identical, but I couldn't find any confirmation or comparison.

What is the difference between doing this:

if (somethingIsTrue) { // like BEGIN
   // do something here
} // like END

BEGIN
    -- Some update, insert, set statements
END

and doing this

BEGIN TRANS
    -- Some update, insert, set statements
COMMIT TRANS

Example: You can do something like this if you want code to be part of a transaction but don't want to create a new one if the code seems to be in one:

declare @TranStarted bit = 0
if @ @trancount = 0
begin
set @TranStarted = 1
begin tran
end

--...do work...

if @TranStarted = 1
begin
commit
set @TranStarted = 0
end

Main Article :- Sql difference between COMMIT and ROLLBACK

The two transactional statements that are used to conduct or undo transactions are the main difference between COMMIT and ROLLBACK. A transaction can consist of a series of queries or update statements that modify the database. If the transaction is completed correctly, the COMMIT statement allows the database modification performed by the transaction to become permanent.

The ROLLBACK statement, on either hand, undoes all the updates if the transaction finishes successfully for some reason. This is the state where the transaction's first statement is in performance. It happens when the transaction is completed successfully.