MySQL usage notes: Related terms and definitions

A database-related terminology

Before we start learning the MySQL database, let's look at some of the terminology of the following RDBMS:

• database: The database is a collection of some associated tables.

• data table: a table is a matrix of data. Tables in a database look like a simple spreadsheet.

• columns: a column (the data element) contains the same data, such as the postal code.

• row: a row (= tuple, or record) is a set of related data, such as a user's subscribed data.

• Redundancy : stores twice times the data, redundancy can make the system faster.

• PRIMARY KEY : The primary key is unique. Only one primary key can be included in a data table. You can use the primary key to query the data.

• foreign Key: A foreign key is used to correlate two tables.

• Composite key : Composite key (key combination) Multiple columns are used as an index key, and are typically applied to composite indexes.

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

• referential integrity: referential integrity requires that references to non-existent entities are not allowed in the relationship. and entity integrity are the integrity constraints that the relational model must satisfy in order to ensure the consistency of the data.

A brief introduction to MySQL II

MySQL is a relational database management system developed by the Swedish MySQL AB company, currently owned by Oracle Corporation. MySQL is an associated database management system that keeps data in separate tables rather than putting all of the data in a large warehouse, which increases speed and increases flexibility.

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

• MySQL supports a large database. You can handle large databases that have thousands records.

• MySQL uses the standard SQL data language form.

• MySQL can be allowed on multiple systems and is supported in multiple languages. These programming languages include C, C + +, Python, Java, Perl, PHP, Eiffel, Ruby, and Tcl.

• MySQL has good support for PHP, which is currently the most popular web development language.

• MySQL support large database, support 50 million records of Data Warehouse, 32-bit system table file maximum support 4gb,64 bit system to support the largest table file is 8TB.

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

This article from "LINUXQT Jinan high-tech Zone" blog, please be sure to keep this source http://qtlinux.blog.51cto.com/3052744/1712842

MySQL usage notes: Related terms and definitions