most used database software

| A | NULL | YES | BTREE | -------------- + ------------- + ----------- + ------------- + ---------- + -------- + -------------- + --------- + 1 row in set (0.00 sec) It is worth noting that indexes are like a double-edged sword. Indexing each field of a table is usually unnecessary and may slow down the operation because MySQL (the best combination with PHP) is used to insert or modify data into the table) you have to re-create an index for th

, and modified fields. These fields provide sufficient information for your project. Prompt If you are not familiar with SQLite,An SQLite command must end with a semicolon. This is helpful if you want to span a command. If the SQLite command is not terminated, press enter to continue giving you a prompt...>. You cannot enter the command at the prompt unless you use a semicolon. Once a semicolon is used, SQLite uses continuous commands as a complete co

This article mainly introduces Mysql database sharding and table sharding methods (commonly used), involving mysql database knowledge, if you are interested in mysql database sharding and table sharding, this article will introduce you to Mysql database sharding and table sh

mytable (name VARCHAR (20), sex CHAR (1),-> birth DATE, birthaddr VARCHAR (20); Query OK, 0 rows affected (0.00 sec) Because the column values of name and birthadd change, VARCHAR is selected, and its length is not necessarily 20. You can choose any length from 1 to 255. If you need to change its font length in the future, you can use the alter table statement .); Gender can be expressed by only one character: "m" or "f". Therefore, CHAR (1) is used,

server| Data | database | statement 1. View the version of the databaseSELECT @ @version2. View the machine operating system parameters of the databaseEXEC master.. xp_msver3. View Database Startup Parameterssp_configure4. View Database Startup timeSelect CONVERT (varchar, login_time,120) from master. sysprocesses where spid=1To view the

The vast majority of applications are closely related to data, such as WEIXIN,QQ, which need to store large amounts of data: contact information, messages sent, friends ' circles, etc. Most of this information is stored in a relational database.Therefore, the Software Test Engineer's understanding of the database is the basic requirement. Specifically, what knowledge should a test engineer have? Let's go th

Frequently-used MySQL database commands: sharing bitsCN.com 1. frequently-used MySQL commands Create database name; create a database Use databasename; select database Drop database nam

What is the server used? Can data be saved? So what is the difference with the database? For example, the user's profile picture is stored on the server. I don't know what the server is. in my mind, there is no concept. I know that the database stores things. it seems that the database cannot save pictures. if the serv

This article mainly introduces the php implementation that can be used for mysql, mssql, and pg database operation classes. it encapsulates operations on mysql, mssql, and pg databases in the form of classes, which is of great practical value, for more information about database operations for mysql, mssql, and PostgreSQL databases, you can modify the

This article mainly introduces the php implementation that can be used for mysql, mssql, and pg database operation classes. it encapsulates operations on mysql, mssql, and pg databases in the form of classes, which is of great practical value, for more information about database operations for mysql, mssql, and PostgreSQL databases, you can modify the

2nd part Database SQL languageMaintenance of the databaseFor some large software products, once commercially, it is necessary to store a lot of user information, which brings pressure on the database used by the product ( hereinafter referred to as the business Database ) .