Getting Started with databases 4 structured Query Language SQL

Knowledge Content:

1.SQL Introduction

2. Common SQL commands

3.SQL Statement Exercise

I. INTRODUCTION of SQL

1. What is SQL

The Structured Query Language (structured query Language) is a special purpose programming language, a database query and programming language for accessing data and querying, updating and managing relational database systems, as well as the extension of database script files. Structured Query language is a high-level, non-procedural programming language that allows users to work on high-level data structures. It does not require the user to specify how to store the data, nor does it require the user to understand how the data is stored, so different database systems with completely different underlying structures can use the same Structured Query language as the interface for data input and management.  Structured Query Language statements can be nested, which gives it great flexibility and powerful functionality. The development of 2.SQL at the beginning of the 1970 was published by Edgar F. Codd, IBM's San Jose,california Research Laboratory, with the principles of applying data to form tables (Codd's relational Algebra). 1974, D.d.chamberlin and R.F of the same laboratory. Boyce to Codd's relational algebra in the development of relational database management system R, developed a set of standard language-sequel (structured English QUEry Language), and published a new version of SQL (called SEQUEL/2) on IBM Journal of the November 1976.　　renamed to SQL in 1980.　　In 1979, Oracle first offered a commercial SQL,IBM company, which also implemented SQL in the DB2 and SQL/DS database systems. October 1986, United States ANSI uses SQL as the standard language for relational database management systems (ANSI X3.　　135-1986), after the adoption of International Organization for Standardization (ISO) as a standard. In 1989, the United States ANSI adopted the SQL standard language of the relational database management system defined in the ANSI x3.135-1989 report, called ANSI SQL 89, which replaces the ANSI x3.135-1986 version.　　The standard is adopted by the following organizations: International Organization for Standardization (ISO), report "Database Language SQL with Integrity enhancement" for ISO 9075-1989 At present (early 21st century) the main relational database management system supports some forms of SQL, most of which are intended to comply with the ANSI SQL89 standard

Ii. Common SQL commands

1.create statements

2. Index statements

3.select statements

III. Practice of SQL statements

1. Creating databases and Tables

2. Enquiry

Getting Started with databases 4 structured Query Language SQL