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DAO and related implementation classes Overview: Data Access Object is a class and interface for accessing data information, including CRUD(Create, regression, Update, Delete) of data, without any business-related information. Sometimes called: BaseDAO. Function: in order to realize the modularization of functions, it is more conducive to cod ...

PostgerSQL object identifier OID OID is an identifier used in PostgreSQL to identify database objects (database, table * *, view, * * stored procedure, etc.), which is represented by an unsigned integer of 4 bytes. It is the primary key of most system tables in PostgreSQL. Type oid represents an object identifier. There are also alias types ...

1. No '' after variable conversion 1.1. Create a stored procedure, which contains a cursor to query the table in a certain mode. It also contains a print of the for loop. The print is added to make the effect of dynamic statements substituted with parameters more intuitive. CREATE OR REPLACE PROCEDURE T_1208(COL VARCHAR(100)) AS CURSOR T_CS ...

Author: Ke Yuchang consultant Software EngineerCurrently engaged in container R & D of RadonDB MySQL, graduated from Huazhong University of science and technology, and has many years of experience in database kernel development.Mastering the reading and debugging ability of MySQL kernel source code is not only the daily work of database R & ...

preface The database needs to be started during backup and closed during recovery 1, What is Xtrabackup? MySQL cold standby, mysqldump and MySQL hot copy cannot realize incremental backup of the database. In the actual production environment, incremental backup is very practical. If the data is greater than 50G or 100G and the stora ...

Objectives of this unit 1, Why learn database 2, Related concepts of database DBMS,DB,SQL 3, Characteristics of database storage data 4, Initial MySQL MySQL Product introduction MySQL Product installation ★ MySQL Start and stop of services ★ MySQL Login and logout of services ★ MySQL Common ...

Performance tuning cases time2021-09-02environmentcentos7. 6. JMeter, redis, mysql, Java applications 1, jmeter's command line uses give an example: # Run in command line mode and execute test JMX test script, and save the test results to result In JTL jmeter -n -t test.jmx -l result.jtl # Specify IP distributed operation jm ...

Detailed explanation of non intrusive AT mode of seata service GlobalTransactional annotation 1. Use this annotation to set the transaction name and timeout time. With this annotation, you will enter the GlobalTransactionalInterceptor in the aspect of Io seata. tm. api. TransactionalTemplate. Execute will assemble the transaction information ...

Basic introduction to XML XML -- Extensible Markup Language. XML features: extensible, tags are user-defined; The grammar is very strict. The role of XML Store data: usually, we store data in a database. However, if you want more portable data, you can store the data in an XML file. Configuration file: it is more used as the configuration ...

IO multiplexing: The IO multiplexing model is based on the demultiplexing function select provided by the kernel. Using the select function can avoid the problem of polling and waiting in the synchronous non blocking IO model. select This function is used to monitor the change of file descriptor - read / write or exception Parameters ...