Structured Query Language (SQL)

What is SQL?

Structured Query Language is a computer language that we use to interact with a relational database. SQL is a tool for organizing, managing, and retrieving archived data from a computer database. The original name was given by IBM as Structured English Query Language, abbreviated by the acronym SEQUEL. When data needs to be retrieved from a database, SQL is used to make the request. The DBMS processes the SQL query, retrieves the requested data, and returns it to us. Rather, SQL statements describe how a collection of data should be organized or what data should be extracted or added to the database.

SQL

Reference: Microsoft

In common usage, SQL encompasses DDL and DML commands for creating, updating, modifying, or performing other operations on the database structure.

Uses of SQL

  • Data definition: It is used to define the structure and organization of the stored data and the relationships among the stored data items.
  • Data retrieval: SQL can also be used for data retrieval.
  • Data manipulation: If the user wants to add new data, remove data, or modify existing data, then SQL provides this facility as well.
  • Access control: SQL can be used to restrict a user’s ability to retrieve, add, and modify data, protecting stored data against unauthorized access.
  • Data sharing: SQL is used to coordinate data sharing by concurrent users, ensuring that changes made by one user do not inadvertently wipe out changes made at nearly the same time by another user.

SQL also differs from other computer languages because it describes what the user wants the computer to do rather than how the computer should do it. (In more technical terms, SQL is a declarative or descriptive language rather than a procedural one.) SQL contains no IF statement for testing conditions and no GOTO, DO, or FOR statements for program flow control. Rather, SQL statements describe how a collection of data is to be organized or what data is to be retrieved or added to the database. The sequence of steps to do those tasks is left for the DBMS to determine.

Features of SQL

  • SQL may be utilized by quite a number of users, including people with very little programming experience.
  • SQL is a non-procedural language.
  • We can, without difficulty, create and replace databases in SQL. It isn't a time-consuming process.
  • SQL is primarily based on ANSI standards.
  • SQL no longer has a continuation individual.
  • SQL is entered into the SQL buffer on one or more extra lines.
  • SQL makes use of a termination individual to execute instructions immediately. It makes use of features to carry out a few formatting tasks.
  • It uses functions to perform some formatting.