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This article mainly explains "what is MySQL". Interested friends may wish to have a look at it. The method introduced in this paper is simple, fast and practical. Now let the editor take you to learn "what is MySQL?"

MySQL is the most popular relational database management system, and MySQL is one of the best RDBMS (Relational Database Management System: relational database management system) applications in WEB applications.

In this tutorial, you will quickly grasp the basic knowledge of MySQL and easily use the MySQL database.

What is a database?

Database (Database) is a warehouse that organizes, stores and manages data according to the data structure.

Each database has one or more different API for creating, accessing, managing, searching, and replicating saved data.

We can also store data in a file, but it is relatively slow to read and write data in the file.

So now we use a relational database management system (RDBMS) to store and manage large amounts of data. The so-called relational database is a database based on the relational model, which deals with the data in the database with the help of mathematical concepts and methods such as set algebra.

RDBMS is the characteristics of relational database management system (Relational Database Management System):

1. The data appears in the form of a table

2. Various record names for each behavior

3. The data field corresponding to the record name of each column

4. Many rows and columns form a form

5. Several forms form database

MySQL is a relational database (Relational Database Management System). This so-called "relational database" can be understood as the concept of "table". A relational database consists of one or more tables, as shown in the figure:

RDBMS terminology

Before we move on to the MySQL database, let's take a look at some of the terms of RDBMS:

Database: a database is a collection of associated tables.

Data table: a table is a matrix of data. A table in a database looks like a simple spreadsheet.

Column: a column (data element) contains the same data, such as postcode data.

Row: a row (= tuple, or record) is a set of related data, such as a piece of data that a user subscribes to.

Redundancy: twice as much data is stored, redundancy reduces performance, but improves data security.

Primary key: the primary key is unique. There can be only one primary key in a data table. You can use the primary key to query data.

Foreign keys: foreign keys are used to associate two tables.

Compound key: compound key (compound key) uses multiple columns as a single index key, which is generally used for composite indexes.

Indexes: use indexes to quickly access specific information in database tables. An index is a structure that sorts the values of one or more columns in a database table. A catalogue similar to a book.

Referential integrity: referential integrity requires that references to entities that do not exist are not allowed in the relationship. And entity integrity is the integrity constraint that the relational model must meet in order to ensure the consistency of the data.

Header (header): the name of each column

Col: a collection of data with the same data type

Row: each line is used to describe the specific information of a record

Value (value): specific information about the row, each value must be the same as the data type of the column

Key: the value of the key is unique in the current column.

MySQL database

MySQL is a relational database management system developed by MySQL AB Company of Sweden and currently belongs to Oracle Company. MySQL is an associated database management system that stores data in different tables instead of all data in a large warehouse, which increases speed and flexibility.

MySQL is open source, so you don't have to pay extra.

MySQL supports large databases. It can handle large databases with tens of millions of records.

MySQL uses the standard SQL data language form.

MySQL can run on multiple systems and supports multiple languages. These programming languages include C, C++, Python, Java, Perl, PHP, Eiffel, Ruby and Tcl.

MySQL has good support for PHP, and PHP is the most popular Web development language at present.

MySQL supports large databases, data warehouses with 50 million records, 32-bit system table files up to 4GB, 64-bit system supports the largest table file is 8TB.

MySQL can be customized, using the GPL protocol, you can modify the source code to develop your own MySQL system.

At this point, I believe you have a deeper understanding of "what is MySQL", might as well come to the actual operation of it! Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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