What is SQL?
- SQL stands for Structured Query Language
- SQL lets you access and manipulate databases
- SQL is an ANSI (American National Standards Institute) standard
SQL (pronounced "ess-que-el") stands for Structured Query Language. SQL is used to communicate with a database. According to ANSI (American National Standards Institute), it is the standard language for relational database management systems. SQL statements are used to perform tasks such as update data on a database, or retrieve data from a database.
RDBMS
RDBMS stands for Relational Database Management System.RDBMS is the basis for SQL, and for all modern database systems such as MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access.
The data in RDBMS is stored in database objects called tables.
A table is a collection of related data entries and it consists of columns and rows.
Writing SQL Statements
Using the following simple rules and guidelines, you can construct valid statements that are both easy to read and easy to edit:• SQL statements are not case sensitive, unless indicated.
• SQL statements can be entered on one or many lines.
• Keywords cannot be split across lines or abbreviated.
• Clauses are usually placed on separate lines for readability and ease of editing.
• Indents should be used to make code more readable.
• Keywords typically are entered in uppercase; all other words, such as table names and columns, are entered in lowercase.