Principles of the transaction processing and recovery of Informix database

Principles of the transaction processing and recovery of Informix database Informix is a widely used relational database management system (RDBMS) with a strong transaction processing and recovery mechanism.Affairs processing is a very important concept in the database management system. It ensures that the data in the database has atomic, consistency, isolation, and persistence (ACID) when adding and deleting operations. Several important concepts of transaction processing include: transactions, rollbacks, commits, and saving points (Savepoint). Affairs refers to a series of statements that operate a database. These statements are either successfully executed and submitted (Commit), or all executes failed and rolled back.The purpose of transaction is to ensure the consistency and integrity of the database. Rolling refers to the revocation of the changes made by the office and the state before the start of the transaction.Rolling can be implemented through the RollBack statement. Submitting refers to the permanent preservation of changes to the office to the database.Submitting can be implemented through the Commit statement. The saving point refers to a mark set in the transaction, which can be rolled back to the operation before the point.You can set the saving point through the Savepoint statement, and you can choose to roll back to the specified save point when rolling. The principle of transaction processing and recovery of the Informix database is based on the log mechanism.The log records each operation of the database, including changes to the table, the beginning and end of the transaction. When performing data changes, Informix will record these changes in the form of logs and operate in memory.Only when the transaction is submitted can the operation be written into the disk. If the system collapses or fails, Informix can be recovered through a log.It checks the log file, finds the recently submitted transactions, and then re -executes these transmitted transactions to enable the database to reach the state before the collapse. In addition to transaction processing and recovery, Informix also provides some configuration parameters to optimize the performance and security of the database. For example, you can control the isolation level by setting the ISOLATION level parameter, including Read Uncommitted, Read Community, Repeningable Read, and Serialization. In addition, you can set the logging parameter to determine whether to enable the log record and the details of the record. By reasonable configuration of the parameters of the Informix database and the processing and recovery mechanism of use, it can ensure the stability and reliability of the database and improve data consistency and completeness. The following is a sample code for using the transaction processing mechanism: sql - Create a storage point SAVEPOINT sp1; -Gen a transaction BEGIN WORK; -Endon some database operations UPDATE table1 SET column1 = value1 WHERE condition1; INSERT INTO table2 (column2) VALUES (value2); -If you need to roll back to the saving point, you can use Rollback to savepoint statement ROLLBACK TO SAVEPOINT sp1; -Submit a transaction COMMIT; It should be noted that the specific implementation of transaction processing and recovery will be different due to different database management systems.The above code is only used for example descriptions. In practical applications, please perform corresponding configuration and programming according to the specific situation. I hope this article will be helpful to understand the principle of transaction processing and recovery of the Informix database!