MySQL Transactions

A transaction in MySQL is a sequential group of statements, queries, or operations such as select, insert, update or delete to perform as a one single work unit that can be committed or rolled back.

1. How do I create a transaction in MySQL?
2. What is the use of start transaction in MySQL?
3. Are MySQL transactions Atomic?
4. What is transaction in InnoDB MySQL?
5. What is transaction in MySQL with example?
6. What are the triggers in MySQL?
7. Should I always use transactions?
8. How do I start a transaction in SQL?
9. Does transaction lock table MySQL?
10. What is acid in MySQL?
11. Does MySQL support DDL triggers?
12. How do I view MySQL transaction logs?

How do I create a transaction in MySQL?

MySQL transaction example

1. First, start a transaction by using the START TRANSACTION statement.
2. Next, select the latest sales order number from the orders table and use the next sales order number as the new sales order number.
3. Then, insert a new sales order into the orders table.

What is the use of start transaction in MySQL?

START TRANSACTION or BEGIN start a new transaction. COMMIT commits the current transaction, making its changes permanent. ROLLBACK rolls back the current transaction, canceling its changes. SET autocommit disables or enables the default autocommit mode for the current session.

Are MySQL transactions Atomic?

A transaction is an atomic unit of database operations against the data in one or more databases. The effects of all the SQL statements in a transaction can be either all committed to the database or all rolled back. MySQL supports several storage engines. The InnoDB is fully ACID compliant.

What is transaction in InnoDB MySQL?

In the InnoDB transaction model, the goal is to combine the best properties of a multi-versioning database with traditional two-phase locking. InnoDB performs locking at the row level and runs queries as nonlocking consistent reads by default, in the style of Oracle.

What is transaction in MySQL with example?

A transaction in MySQL starts with the first executable SQL statement and ends when it finds a commit or rolled back either explicitly or implicitly. It explicitly uses COMMIT or ROLLBACK statement and implicitly when a DDL statement is used.

What are the triggers in MySQL?

In MySQL, a trigger is a stored program invoked automatically in response to an event such as insert, update, or delete that occurs in the associated table. For example, you can define a trigger that is invoked automatically before a new row is inserted into a table.

Should I always use transactions?

The primary benefit of using transactions is data integrity. Many database uses require storing data to multiple tables, or multiple rows to the same table in order to maintain a consistent data set. Using transactions ensures that other connections to the same database see either all the updates or none of them.

How do I start a transaction in SQL?

1. --Applies to SQL Server and Azure SQL Database BEGIN TRAN | TRANSACTION [ transaction_name | @tran_name_variable [ WITH MARK [ 'description' ] ] ] [ ; ]
2. BEGIN TRAN T1; UPDATE table1 ...; BEGIN TRAN M2 WITH MARK; UPDATE table2 ...; SELECT * from table1; COMMIT TRAN M2; UPDATE table3 ...; COMMIT TRAN T1;

Does transaction lock table MySQL?

Also, beginning a transaction (for example, with START TRANSACTION) implicitly performs an UNLOCK TABLES. As of MySQL 4.0. 2, to use LOCK TABLES you must have the LOCK TABLES privilege and a SELECT privilege for the involved tables.
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What is acid in MySQL?

MySQL fully satisfies the ACID requirements for a transaction-safe RDBMS, as follows: Atomicity is handled by storing the results of transactional statements (the modified rows) in a memory buffer and writing these results to disk and to the binary log from the buffer only once the transaction is committed.

Does MySQL support DDL triggers?

2 Answers. MySQL only supports triggers for BEFORE / AFTER INSERT , UPDATE , DELETE , see documentation for the CREATE TRIGGER syntax. ... Maybe another option would be to create the view "if not exists" whenever a row of data is INSERT ed into the table, in which case you could use a BEFORE INSERT trigger.

How do I view MySQL transaction logs?

If you're using MySql on Windows, there's a file located in C:\Program Files\MySQL\MySQL Server 5.0\data (assuming a C: drive for the installation target and MySql version 5.0), that is called %COMPUTERNAME%. log that contains the commands that have been executed.