MySQL database FAQ

MySQL database FAQ
1. Transaction Features and isolation level:

See blog: http://www.cnblogs.com/Hangtutu/p/8016663.html

2. View

View is a virtual table, which is transparent to users who use views. View and
Does not actually exist in the database. The row and column data are used in the query of the custom view.
Dynamically generated
Simple: users who use a view do not need to care about the structure, association conditions, and filtering conditions of the corresponding table,
This is already the result set of the filtered compound condition.
Security: View users can only access the result sets they are allowed to query, but cannot manage table permissions.
Restrict a column in a row, but you can simply implement it through the view.
Data independence: Once the view structure is determined, the impact of table structure changes on users can be shielded, increasing the number of source tables.
The column does not affect the view. To modify the column name in the source table, you can modify the view to avoid access
Influence

3. Differences between MyISAM and Innodb

(1) MyISAM does not support transactions. Innodb supports transactions.

(2) Myisam does not support foreign keys. innodb supports foreign keys.

(3) myisam supports table-level locks and innodb supports row-level locks.

(4) When innodb performs select count (*) from tablename, it needs to traverse the table once; When myisam performs select count (*) from tablename

(5) When myisam deletes a table, it first drops the table and creates a new table. innodb deletes the data in the table one by one.

(6) For indexes that contain the auto-increment field, innodb only contains the auto-increment field, while myisam can create a joint index with other fields.

(7) myisam search engine search is faster than innodb Search Engine

(8) indexes in innodb do not have the fulltext type, while myisam does not have the fulltext type.