What is the difference between mysql and db2

The difference between mysql and db2: 1. Mysql can authorize the smallest unit of objects in batches, but db2 cannot authorize the smallest unit of objects in batches; 2. Mysql supports opening the database during recovery, while db2 Opening the database during recovery is not supported.

The operating environment of this tutorial: windows10 system, mysql8.0.22 version, Dell G3 computer.

What is the difference between mysql and db2

IBM DB2 is a relational database management system developed by IBM in the United States. Its main operating environment is UNIX (including IBM's own AIX), Linux, IBM i (formerly OS/400), z/OS, and Windows server versions. DB2 is mainly used in large-scale application systems. It has good scalability, can support everything from mainframe to single-user environments, and can be used on all common server operating system platforms.

MySQL is a relational database management system. A relational database stores data in different tables instead of putting all data in one large warehouse, which increases speed and flexibility. The SQL language used by MySQL is the most commonly used standardized language for accessing databases. MySQL software adopts a dual licensing policy and is divided into community version and commercial version. Due to its small size, fast speed and low total cost of ownership, especially the characteristics of open source, MySQL is generally chosen as the website database for the development of small and medium-sized websites.

1. Account management method

The MySQL account management method is similar to Oracle. It is managed by MySQL itself. The account is stored in the user table of the MySQL database. The account number is The composition is composed of IP address and user name, and DB2 does not have its own user system, and its authentication completely depends on the operating system account.

2. Permission management method

Mysql can authorize the smallest unit of objects in batches; DB2 cannot, which is relatively cumbersome.

3. Log management

The MySQL database uses log double writing to ensure the integrity and recoverability of data. MySQL has two transaction logs and archive logs. Independent objects without any causal relationship. The archive logs of the DB2 database are generated by transaction logs.

4. Lock management method

MySQL uses the MVCC model to implement lock concurrency control, and DB2 uses the memory model to implement lock concurrency control. In concurrent processing, processing In terms of resource conflicts, MySQL is superior to DB2 in terms of its concurrent processing capabilities and lock conflict methods.

5. Schema management method

Strictly speaking, MySQL database does not have the concept of schema, and each schema is equivalent to an independent database. The db2 database can create multiple schemas in one database.

6. Table space management method

The MySQL database has relatively weak support for table spaces and has many limitations. In striping and space management There are weaknesses. DB2 is very perfect in these aspects, with convenient management, powerful functions, and easy maintenance.

7. Transaction behavior

MySQL will roll back to the previous save point and will not roll back the entire transaction; DB2 will roll back the entire transaction.

8. Data recovery

MySQL supports opening the database during recovery, which is flexible; DB2 does not support opening the database during recovery or rollforward.

9. SQL support

MySQL has weak support for complex SQL and may have performance problems during runtime; DB2 supports various complex SQL and multiple jion methods .

10. Syntax differences

MySQL complies with the SQL92 standard, but there are differences in details, and the default is case-sensitive; DB2 complies with the SQL92 standard and is not case-sensitive.

11. High availability and disaster recovery design

MySQL has many solutions for high availability and disaster recovery. MySQL natively supports multiple architectures and replication solutions. It completes the high availability and disaster recovery requirements of the database such as MHA, PXC and MMM. It is also very flexible and can be customized and re-developed according to business needs at almost zero cost. DB2 only has HADR solution in this regard and the cost is high.

12. Scalability

MySQL also has many solutions for clustering, such as Cobar, Atlas, Fabric, Amoeba, TDDL, Mycat, and they can be customized Or carry out secondary development, which can be flexibly expanded according to business needs. DB2 currently has only one solution, PureScale, in this regard, which is less flexible.

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