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SQL INTRODUCTION
What is SQL?
SQL or called Structure Query Language is used to accessing and manipulating database.SQL is a standard language for storing, manipulating and retrieving data in databases. We can use SQL in: MySQL, SQL Server, MS Access, Oracle, Sybase, Informix, Postgres, and other database systems.
SQL becomes standard of the International Organisation for Standardisation (ISO) in 1987 and for American National Standards Institute (ANSI) in 1986.
What Can SQL Do?
By using SQL we can:
- execute queries against a database
- retrieve data from a database
- insert records in a database
- update records in a database
- delete records from a database
- create new databases
- create new tables in a database
- create stored procedures in a database
- create views in a database
- set permissions on tables, procedures, and views
SQL is Standard But?
However, to be compliant with the ANSI standard, they all support at least the major commands (such as SELECT, UPDATE, DELETE, INSERT, WHERE) in a similar manner.
Using SQL in your WEB SITE:
To build a web site that shows data from a database, you will need:
- An RDBMS database program (i.e. MS Access, SQL Server, MySQL)
- To use a server-side scripting language, like PHP or ASP
- To use SQL to get the data you want
- To use HTML / CSS to style the page
RDBMS
RDBMS stands for Relational Database Management System.
An RDBMS is a DBMS designed specifically for relational databases or SQL database. An RDBMS may also provide a visual representation of the data. For example, it may display data in a tables like a spreadsheet, allowing you to view and even edit individual values in the table. RDBMS is the basis for SQL, and for all modern database systems such as MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access.
SQL is used in the accessing, updating, and manipulation of data in a database while MySQL is an RDBMS that allows keeping the data that exists in a database organised. SQL is a Structured Query Language and MySQL is a RDBMS to store, retrieve, modify and administrate a database. 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.It is basically a relationships between data items are expressed by means of tables.
Every table is broken up into smaller entities called Fields. The fields in the Customers table consist of CustomerID, CustomerName, ContactName, Address, City, PostalCode and Country. A field is a column(vertical) in a table that is designed to maintain specific information about every record in the table. A record, also called a row(horizontal), is each individual entry that exists in a table.
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