Sql database is very important part of our day to day life of software development.Lets have some look on basis of Database fundamentals.
What is SQL?
- SQL stands for structured Query Language. it is a standard query language used for managing relational Databases and performing various operations on the data.
- It is initially created in the 1970.it is used by database administrator as well as by developers for writing data integration scripts.
- Some common relational database management system that uses sql are: oracle, Sybase, Microsoft sql server, Access, Ingres etc.…
- It store data in one or more objects called tables.
What is the use of SQL?
- The uses includes modifying database tables and index structures.
- Inserting, updating, deleting rows of data.
- Retrieving subset of data from database for transaction processing and analytics applications.
- This language is based on several elements. For the convince all command are usually executed through a specific SQL command line interface(CLI).
- Clause: the clauses are components of the statements and Query.
- Expressions: it produces scalar value or tables, which consists of columns and rows of data.
- Predicates: if specify conditions, which are used to limit the effect of the statement and to change the flow of the program.
- Queries: it retrieves data, based on specified predicates.
- Statements: statements are used for sending queries from a client program to a server where the databases are store.
There are three main statements:
- DML stands for data manipulation language.
- Used to query and manipulate data.
- DML includes Select, Insert, Update, Delete query.
- DDL stands for data definition language.
- Used to define database objects.
- DDL includes Create, Alter, Drop query.
- DCL stands for data control language.
- Used to manage security permissions.
- DCL includes Grant, Revoke, Deny query.
Keep Visiting TechwithR.com for more upcoming top technical articles.