SQL is a relational database management system deployed in several systems like Oracle, Microsoft SQL Server, Sybase, and Access etc. Structured Query Language or SQL used for database management is not a programming language. But its standard allows the creation of procedural extensions for it that imparts the maturity of a programming language into it. Oracle V2 was the first database management system that used SQL in 1979 and ANSI accorded it an official standard in 1986 and ISO did the same in 1987.
SQL allows communication with and between databases that is essential for managing data contained in the databases. Well, this brief description does not help to view the vast functionalities of SQL and to understand it, you must keep reading this article.
No business can exist today without making use of data for which they must rely on some robust database management by using the powers of SQL. Proper data analysis helps to make critical business decisions, and by exploiting the powers of databases, organizations can improve business performance. Managing data is not an easy job and best done by database administrators like the experts at RemoteDBA.com who work behind the scenes and contribute immensely to business success.
What is SQL?
All data related to digital applications remain stored in a database. For example, apps like Google Chrome or Facebook or Twitter store all user-related information as well as data about their online activities and communications in a database. SQL is the language used by programmers to work on databases and use data to retrieve important information. Applications use different programming languages like PHP, Python or Ruby, but the configuration of databases does not allow understanding these languages because databases run on SQL. Therefore, it becomes imperative for web developers and app developers to learn SQL to undertake database management.
Database tables
To use SQL effectively, a programmer must first learn SQL markup and even understand the concept to tables, which is an essential feature of database management. A database consists of several tables, as evident from 11 tables used in WordPress and each table represents a specified data set arranged in the form of columns and rows.
SQL commands
To start using SQL, you must be familiar with some frequently used commands.
CREATE DATABASE – The command is self-explanatory.
CREATE TABLE – This command does not need any explanation.
SELECT – Use this command to locate any data in the database and extract it.
UPDATE – Edit data and make changes.
DELETE – To remove data.
These are the elementary commands, and the bigger the database more is, the complexity and programmers use many more advanced commands to perform tasks. Commands help to initiate or write inquiries/queries for working with data in the databases. By entering a command in the database, you communicate with the system that interprets the data to understand the requested task and then process the command to execute the task. It might relate to the creation of a new database or incorporating new data into the database.
Here are some advanced SQL commands.
EXPRESSIONS – The command is useful for creating tables comprising of rows and columns or producing scalar values.
CLAUSES – These are components of different statements and queries.
QUERIES – The command is useful for retrieving data based on specified criteria, and you must have an understanding of some basic queries of SQL.
PREDICATES – The command specifies the conditions used by programmers for limiting the effects of Statements and Queries or to change the flow of the program.
STATEMENTS – The command helps to control program flow, transactions, sessions, connections and diagnostics and used for generating queries from a client program to the database. It facilitates faster data manipulation.
SQL sublanguages
SQL consists of 4 principal sublanguages, namely DDL, DML, DCL and TCL.
DDL – Data Definition Language or DDL is used for defining data structures within the databases. By using DDL statements, you can create modify and destroy specific database objects. The type of DBMS stipulates the kind of object that can be handled but usually includes tables, users and some smaller objects like roles and indexes.
DML – Data Manipulation Language or DML is used for initiating a query and changing data contained in the database. By using DML statements, you can select and insert data in the tables as well as update and delete them. DML statements used for SQL are declarative, and since pure select statements do not change the state of the data, it is not considered as part of DML.
DCL – Data Control Language is used for access control of data stored in the databases. DCL statements abound in privileges, and you can grant and revoke privileges regarding applying certain DDL and DML commands to certain objects in the database.
TCL – Transaction Control Language or TCL is used for controlling the processing of transactions in the databases.
Common database systems
Database systems are software programs that developers use for working on databases with the help of the user interface. Tools like builders, templates and constructors contained in the databases make the life of database programmers easier.
Now we will discuss some common database systems.
MySQL – This is an open-source database and highly popular with startups and small businesses because it is free. Being open-source software MySQL finds wide application in application and software development.
Oracle database – Oracle is the world leader in the SQL database system. A wide range of industries use Oracle databases, but it is especially popular for processing online transactions and in data warehousing.
Microsoft SQL Server – Microsoft’s database system comes by the name SQL server, and it runs on all kinds of Windows operating systems (OS). It finds extensive use in Windows-based web servers and even in consumer software while enjoying a huge user base.
PostgreSQL – PostgreSQL is also an open-source DBMS (database management system) that is very popular among technology startups because of free availability. PostgreSQL supports a variety of operating systems like Windows, Linux and macOS. The database makes more use of SQL syntax than other databases.
To start learning about databases and hone your skills in database management, open-source databases like MySQL and PostgreSQL are most suitable.