Technical terms in MYSQL database

Before you start to learn the MySQL database, understand the technical terms in the MYSQL database to show that you know and use the data well enough.

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

Row: a collection of data with the same data type

Col: 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 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.

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