Currently, Data is the foundation of any business. Understanding Big data and Databases is an essential skill to enter today’s data-driven world. Learning SQL is a quick and easy method to get started. In this blog, let us discuss the popular database language- SQL. Become an expert in SQL with a top SQL Certification Online.
What is SQL?
SQL stands for Structured Query Language. The SQL language is the industry standard for working with Relational Database System(RDBMS). SQL may do a variety of different tasks such as Inserting, searching, updating, and deleting database records including database optimization and maintenance.
SQL is used by all Relational Database Management Systems such as MySQL, MS Access, Oracle, Sybase, Informix, Postgres, and SQL Server. Know more about What is SQL with a comprehensive blog.
What is the History of SQL?
The following is a history of SQL’s development. How it has changed since 1970.
- Edgar F. Codd of IBM first introduced a relational database model in 1970.
- Later, The Structured Query Language (SQL) was first published in 1974.
- The System/R is a product launched by IBM in 1978.
- In 1986, IBM created the first relational database prototype, which is standardized by ANSI.
- And in 1989, The first version of SQL was released.
What is the Purpose of SQL?
SQL is frequently used in databases. The following listed points are the reasons why we use SQL.
- To understand and explain the data.
- To construct database views, stored procedures, and functions.
- To gain access to data stored in relational database management systems.
- To build and delete databases and tables.
- To specify and manage the data in a database.
- To change permissions for tables, methods, and views.
- To gain access to only selected sections without downloading data.
More information about SQL in the video below –
What are the Types of SQL Statements and Commands?
The following sections provide you a list of various popular SQL statements along with their commands.
- Data Definition Language (DDL): Data Definition Language modifies the table’s structure, such as by adding, removing, or modifying a table. The DDL commands are as follows:
- CREATE: It’s used in the database to create a new table.
- ALTER: It’s used to modify the database’s structure.
- DROP: It’s utilized to delete the table’s structure as well as its records.
- TRUNCATE: It’s used to remove all the rows in a table and free up the space it’s in.
- Data Manipulation Language (DML): The database is modified by using Data Manipulation Language instructions. It is in charge of all database updates of any kind. The following are commands that come under DML.
- INSERT: It is used to insert data into a table’s row.
- UPDATE: It is used to change or update the value of a table column.
- DELETE: It’s used to get rid of one or more rows in a table.
- Data Control Language (DCL): Any database user can be granted or revoked authority using Data Control Language commands. There are two commands in DCL which are as follows:
- GRANT: It is used to provide users database access capabilities.
- REVOKE: It’s used to revoke the user’s permissions.
- Transaction Control Language (TCL): Only DML commands like INSERT, DELETE, and UPDATE can be used with TCL commands. The following are the commands of TCL.
- COMMIT: All transactions are saved to the database using the commit command.
- ROLLBACK: The rollback command is used to reverse transactions that haven’t been recorded to the database yet.
- SAVEPOINT: It’s used to roll back a transaction to a specific point rather than the full transaction.
- Data Query Language (DQL): The data is retrieved from the database using Data Query Language. It has only a single command.
- SELECT: It is used to choose an attribute depending on the WHERE clause’s condition.
What is SQL Process?
When you run a SQL command against any RDBMS, you must first select the appropriate way for carrying out your request so that the system works out the best way to carry out your request, and the SQL engine figures out how to understand it.
This procedure has a number of different components. The following are important components of the SQL process:
- Classic Query Engine: Non-SQL queries are handled by the classic query engine.
- SQL Query Engine: To access data in relational systems, a SQL query engine understands SQL instructions and language. The SQL query engine does not support logical files.
- Optimization Engines: SQL optimization is the practice of utilizing SQL queries in the most efficient manner feasible in order to obtain correct and timely database results.
- Query dispatcher: The dispatcher’s job is to forward the query request to either CQE or SQE, based on the query’s characteristics. All inquiries should be directed to the dispatcher.
How to Use SQL?
This is the process to use SQL. The SELECT statement is used to query or retrieve information from a SQL database.
SELECT * FROM Employees WHERE ID=10
Although many RDBMS employ a few distinct commands and even proprietary SQL syntaxes, SQL syntaxes used in multiple databases are almost identical.
What are SQL elements?
In this section, let’s discuss some of the popular SQL elements.
- Strings: Strings can be literal strings or VARCHAR or CHAR data types expressions.
- Identifiers: An identifier is the representation of items generated by the user within the language. Examples of Identifiers are user IDs, tables, and columns.
- Keywords: A single or more keywords can be found in each SQL query.
- Variables: Local variables, global variables, and connection-level variables are all supported by Sybase IQ.
- Expressions: Constants, SQL operators, column names, and subqueries are all used to construct expressions.
- Comments: Another SQL element used to attach explanatory text to SQL statements or sets of statements is the comment. Any comment is not executed by the database server.
Are SQL Skills in Demand?
Most businesses want someone who is familiar with SQL. Salaries for SQL-related jobs vary depending on the job type and expertise, but they are typically higher than average. To help you prepare for these roles, it’s important to review common SQL Interview Questions that you may encounter during the hiring process.
The following are some examples of jobs that require SQL knowledge:
Database Administrator (DBA): A database administrator ensures that data is saved and maintained correctly and effectively. Databases are most useful when they allow users to rapidly and easily obtain required data combinations.
Database Migration Engineer: This individual specializes in transferring data from many databases to a SQL server.
Data Scientist: This is a profession that is very similar to the data analyst, however, data scientists are generally entrusted with managing considerably larger amounts of data and gathering it at much faster speeds.
Bigdata Architect: A big data architect is someone who creates products for dealing with enormous amounts of data.