The SQL Full Form is Structured Query Language.
What is SQL?
Is a standard Database language used to carry out different operations in a database? It is a language by which we can create, maintain and retrieve the relational database. SQL operates based on relational algebra and tuple relational calculus. With the help of SQL, we can create, delete databases, fetch rows and modify them. To perform SQL queries, you need to install databases like Oracle, MySQL, MongoDB, PostgreSQL, SQL Server, DB2, etc.
In a database, the tables are broken up into smaller entities called a field, which is the table’s column in simple words. A field is designed to maintain specific information stored in the rows of the table.
The Structured Query Language (Full Form of SQL) consists of 3 sublanguages that are used to manipulate and control the database. These are DDL (Data Definition Language), DML (Data Manipulation Language), DCL (Data Control Language).
- DDL deals with database schemas and descriptions of how the data should reside in the database. It includes the SQL commands like CREATE, ALTER, DROP, TRUNCATE, COMMENT, RENAME.
- DML deals with data manipulation, and it is used to store, modify, retrieve, delete and update data in a database. It includes the most common SQL statements such as SELECT, INSERT, UPDATE, DELETE, etc.
- DCL is concerned with permissions, rights, and other controls of the database system. The commands used in this language are GRANT, REVOKE.
We can retrieve data from two different database tables with the help of SQL Joins (Left Join, Right Join, Inner Join, Outer Join). The basic SQL commands used are Create, Update, Alter, Select, Insert.
- Create command is used to create tables in the database.
- The update command is used to manipulate data stored in the tables of the database.
- Alter command is used to update the fields of the tables.
- The select command is used to recover data from the database.
- Insert command is used to insert data into the fields of the table.
The SQL contains some predefined arithmetic functions like max(), min(), count(), sum(), which returns the maximum, minimum values of the selected column, count of the unique fields, and some of the data present in the field of the table respectively.
Advantages of SQL
- Structured Query Language, a full form of SQL, is considered an open-source programming language. Hence it has a huge community of developers.
- Database technologies like MySQL, Microsoft SQL, PostgreSQL Server are used in many organizations like small companies, banks, hospitals, colleges.
- The portability feature of SQL makes it easy to be used on PCs, servers, laptops, and even some mobile phones.
Disadvantages of SQL
- Some users find difficulty in accessing the SQL interface.
- One cannot have full control over the database because of its hidden business rules.
- The Vendor lock-in feature in some databases used for a proprietary extension creates difficulty for some users.