How to operate MySQL database with PHP - how to select a database file. In our daily PHP development work, when we want to obtain data from the database, after PHP connects to the database, the next step is to select the database file. A function is used, the mysql_select_db() function selects the database! Before choosing a database, the first thing we do is connect PHP to the database. We have detailed how to establish a connection in the previous article "Using the mysql_connect() function to connect to the database (Method 1 of PHP operating MySQL database)". I won’t introduce much here. Today we will mainly talk about the mysql_select_db() function! The syntax format of the mysql_select_db() function is as follows: mysql_select_db(string database name[,resource link_identifier]) or: mysql_query("use database name"[,resource&
1. About mysql_select_db() Recommended 10 articles
## Introduction: How to operate MySQL database with PHP - How to select the database file in our In daily PHP development work, when we want to obtain data from the database, after PHP connects to the database, the next step is to select the database file, and we need to use a function, the mysql_select_db() function to select the database! , the first thing we do is to connect PHP to the database, which we discussed in the previous article "Using the mysql_connect() function to connect to the database (PHP method for operating MySQL database...
2 . Detailed introduction to selecting database files
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Use the mysql_select_db() function to select the database file (method 2 of PHP operating MySQL database)
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The difference between mysql_db_query and mysql_queryIntroduction: I won’t talk about the difference. Yes, you will know after reading the above example. The main difference is that there is one more mysql_select_db. Regarding performance, the use of this function is not recommended since PHP 4.0.6. Do not use this function. Use mysql_select_db() and mysql_query() instead.
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CAPI function description (S-W)Introduction: 25.2.3.59. mysql_select_db() int mysql_select_db( MYSQL *mysql, const char *db) Description Makes the database specified by db the default database (current database) on the connection specified by mysql. In subsequent queries, this database will be the default database referenced by tables that do not contain an explicit database separator. Unless you are connected, use
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PHP Self-study Tutorial for MySQL DatabaseIntroduction: PHP access to MySQL database General steps: 1. Connect to MySQL database: Use the mysql_connect() function to establish a connection with the MySQL server. 2. Select the MySQL database: Use the mysql_select_db() function to select the database on the MySQL database server. 3. Execute the SQL statement: use the mysql_query() function in the selected database
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MySQL backup policies include logical backup, physical backup, incremental backup, replication-based backup, and cloud backup. 1. Logical backup uses mysqldump to export database structure and data, which is suitable for small databases and version migrations. 2. Physical backups are fast and comprehensive by copying data files, but require database consistency. 3. Incremental backup uses binary logging to record changes, which is suitable for large databases. 4. Replication-based backup reduces the impact on the production system by backing up from the server. 5. Cloud backups such as AmazonRDS provide automation solutions, but costs and control need to be considered. When selecting a policy, database size, downtime tolerance, recovery time, and recovery point goals should be considered.

MySQLclusteringenhancesdatabaserobustnessandscalabilitybydistributingdataacrossmultiplenodes.ItusestheNDBenginefordatareplicationandfaulttolerance,ensuringhighavailability.Setupinvolvesconfiguringmanagement,data,andSQLnodes,withcarefulmonitoringandpe

Optimizing database schema design in MySQL can improve performance through the following steps: 1. Index optimization: Create indexes on common query columns, balancing the overhead of query and inserting updates. 2. Table structure optimization: Reduce data redundancy through normalization or anti-normalization and improve access efficiency. 3. Data type selection: Use appropriate data types, such as INT instead of VARCHAR, to reduce storage space. 4. Partitioning and sub-table: For large data volumes, use partitioning and sub-table to disperse data to improve query and maintenance efficiency.

TooptimizeMySQLperformance,followthesesteps:1)Implementproperindexingtospeedupqueries,2)UseEXPLAINtoanalyzeandoptimizequeryperformance,3)Adjustserverconfigurationsettingslikeinnodb_buffer_pool_sizeandmax_connections,4)Usepartitioningforlargetablestoi


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