Last Updated on December 7, 2023 by GeeksGod

Course : SQL From Basics to Advanced & Sql interview(Beginner to Pro)

Why SQL

SQL (Structured Query Language) is an essential tool for anyone working with databases. It offers numerous benefits and functionalities that make it a popular choice among developers and data analysts.

Benefits of SQL

Store large number of records

SQL allows you to store vast amounts of data efficiently. This is particularly important for businesses or organizations that handle large datasets and need a reliable way to manage and organize information.

Share huge data set among many people

SQL provides a centralized platform for sharing data with multiple users. It allows simultaneous access and seamless collaboration, making it easier for teams to work together on projects and analysis.

Add and edit data easily

With SQL, you can easily add, update, and delete data within a database. It provides a simple and intuitive way to modify records, ensuring data accuracy and consistency.

Quick and easy to find information

SQL offers powerful query capabilities that allow you to search for specific data quickly. This is especially useful when dealing with large datasets, as it saves time and effort in finding relevant information.

RDBMS Terminology

Before diving into SQL, it’s essential to understand some common RDBMS (Relational Database Management System) terminology:

Column as Attribute

In a database table, each column represents an attribute that describes the characteristics of the data being stored.

Row as Entity Instance

A row, also referred to as a record, represents a single instance or entity within a table. It contains multiple attributes and holds specific values for each attribute.

Table as Entity

A table is a collection of rows and columns that represent a specific entity or object. It organizes related data in a structured format to facilitate data retrieval and manipulation.

AlternateKey as UniqueKey

An alternate key is a column or combination of columns that uniquely identify each row in a table. It serves as an alternative to the primary key and is used when multiple columns can uniquely identify a record.

Relationships

In a relational database, tables are often interconnected through relationships. The relationships between tables define how data is related and allow for efficient data retrieval. There are three types of relationships:

One-to-One

In a one-to-one relationship, each record in one table is associated with only one record in another table. It is a direct link between two tables using a common key.

One-to-Many

In a one-to-many relationship, one record in a table can be associated with multiple records in another table. This is the most common type of relationship in databases.

Many-to-Many

In a many-to-many relationship, multiple records in one table can be associated with multiple records in another table. To represent this relationship, a bridge table is created with additional columns that link the primary keys of both tables.

Data Modeling

Data modeling is a critical aspect of database design. It involves defining the structure, relationships, and constraints for a database. The most commonly used data modeling technique is the Entity-Relationship Diagram (ERD).

Entity-Relationship Diagram (ERD)

An ERD is a visual representation of entities, their attributes, and the relationships between them. It helps to conceptualize and design the database structure, making it easier to understand and communicate the database’s architecture.

Referential Integrity

Referential integrity ensures that the relationships between tables are maintained. The database management system (such as SQL Server) performs an existence check when creating relationships to ensure that the referenced records exist in the associated table.

SQL Course Topics

In this SQL course, you will learn the following topics:

Commands (DDL, DML, DQL, DCL, TCL)

Understand the different types of SQL commands, including Data Definition Language (DDL), Data Manipulation Language (DML), Data Query Language (DQL), Data Control Language (DCL), and Transaction Control Language (TCL).

Data Types

Learn about the various data types supported by SQL, such as numeric, string, date/time, and boolean. Understanding data types is crucial for proper data storage and manipulation.

Constraints

Explore the different constraints that can be applied to SQL tables, including NULL, DEFAULT, PRIMARY KEY, UNIQUE, FOREIGN KEY, CHECK, and AUTO_INCREMENT. Constraints ensure data integrity and enforce specific rules on table columns.

Views

Discover views, which are virtual tables derived from one or more tables. Views allow you to simplify complex queries, encapsulate logic, and present data in a customized way without modifying the underlying tables.

Operators

Learn about SQL operators such as arithmetic operators, comparison operators, logical operators, and string operators. Operators are used to perform various calculations and comparisons within SQL statements.

Query Writing

Develop skills in writing SQL queries to extract, manipulate, and analyze data from databases. This includes retrieving specific data, filtering records, sorting results, and combining multiple tables using joins.

Joins

Explore different types of joins, including inner join, outer join, self-join, and cross join. Joins are used to combine data from multiple tables based on related columns.

Subquery

Understand subqueries, which are nested SQL queries used within other SQL queries. Subqueries can be used to retrieve intermediate results, filter data, or perform complex calculations.

Derived Table

Learn about derived tables, which are temporary tables created within a SQL query. Derived tables allow you to perform calculations or filter data on the fly without explicitly creating a permanent table.

Indexes

Explore indexes, which improve the performance of SQL queries by speeding up data retrieval. Indexes are created on specific columns and allow for faster searching, sorting, and joining of data.

Stored Procedures

Discover stored procedures, which are precompiled sets of SQL statements stored in the database. Stored procedures can be invoked by applications to perform repetitive tasks, improve security, and simplify database operations.

Triggers

Learn about triggers, which are database objects that execute automatically in response to specific events or actions happening within the database. Triggers can be used to enforce business rules, audit changes, or automate tasks.

Functions

Understand functions, which are predefined SQL routines that accept parameters, perform calculations, and return values. Functions can be used to simplify complex logic or perform common calculations within SQL queries.

Cursors

Explore cursors, which are database objects that allow iterative processing of SQL query results. Cursors can be used to retrieve and process data row by row, providing additional flexibility and control over data manipulation.

Start your journey in SQL with this comprehensive course and unlock the power of databases for your projects and career growth! Remember to grab the Free Udemy Coupon for this SQL course and begin your learning journey instantly.