Databases can be found in almost all software applications. SQL is the standard language to query a database. 


What is a DBMS?

A database management system (DBMS) is a software used to store and manage data. It guarantees the quality, durability, and confidentiality of information. The most popular type of DBMS are Relational Database Management Systems, or RDBMS's. Here, the database consists of a structured set of tables and each row of a table is a record.

What is SQL?

SQL


Structured Query Language (SQL) is the standard language for data manipulation in a DBMS. In in simple words its used to talk to the data in a DBMS. Following are types of SQL Statements
  1. Data Definition Language (DDL) allows you to create objects like Schemas, Tables in the database
  2. Data Control Language (DCL) allows you to manipulate and manage access rights on database objects
  3. Data Manipulation Language (DML) is used for searching, inserting, updating, and deleting data, which will be partially covered in this programming tutorial.

What is Query?

A Query is a set of instruction given to the database management system. It tells any database what information you would like to get from the database. For example, to fetch the student name from the database table STUDENT, you can write the SQL Query like this:
SELECT Student_name from STUDENT;

Also Read: What is Database? What is SQL

SQL Process

When you want to execute an SQL command for any DBMS system, you need to find the best method to carry out your request, and SQL engine determines how to interpret that specific task.
Important components included in this SQL process are:
  • SQL Query Engine
  • Optimization Engines
  • Query Dispatcher
  • Classic Query Engine
A classic query engine allows you to manage all the non-SQL queries.
sql tutorial

SQL Optimization

Knowing how to make queries is not too difficult, but you need to really learn and understand how data storage works, and how queries are read in order to optimize SQL performance. Optimizations are based on two key factors:
  1. Making the right choices when defining the database structure
  2. Applying the most appropriate methods to read the data.

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