Structured Query Language (Sql) - Part 1

This section introduces Structured Query Language (SQL), emphasizing essential commands for defining database structures and manipulating data.

Introduction To Sql: History And Standards

This section introduces SQL, its historical origins, and the importance of SQL standards in ensuring interoperability across different database systems.

What Is Sql?

SQL is the standard declarative language used to manage and manipulate data in relational databases.

History Of Sql

This section provides an overview of the origins and evolution of Structured Query Language (SQL) and its standardization.

Sql Standards

SQL standards ensure compatibility across different database systems, facilitating seamless data management.

Data Definition Language (Ddl)

This section introduces Data Definition Language (DDL), a vital part of SQL that defines, modifies, and deletes database structures.

Create Table Statement

The CREATE TABLE statement is utilized to define a new table in a database, specifying its name, columns, and constraints.

General Syntax

The General Syntax of SQL's CREATE TABLE command outlines how to define a new table's structure, including its attributes and constraints.

Example Of Create Table

This section outlines the syntax and usage of the CREATE TABLE statement in SQL, essential for defining new tables in a database.

Defining Constraints

Constraints are rules applied to database tables that ensure data integrity and consistency.

Primary Key Constraint

The PRIMARY KEY constraint uniquely identifies each record in a table, ensuring data integrity.

Foreign Key Constraint

The FOREIGN KEY constraint is a fundamental aspect of relational databases that enforces referential integrity between tables.

Not Null Constraint

The NOT NULL constraint is used to ensure that a column cannot have NULL values, thereby enforcing data integrity.

Unique Constraint

The UNIQUE constraint ensures that all values in a specified column are distinct across all records, enhancing data integrity in databases.

Check Constraint

The CHECK constraint in SQL defines specific conditions that values in a column must satisfy, ensuring data integrity when inserting or updating records.

Default Constraint

The DEFAULT constraint is used to provide default values for a column in a table during an INSERT operation when no explicit value is provided.

Alter Table Statement

The ALTER TABLE statement modifies the structure of an existing database table by adding, dropping, or changing columns or constraints.

Common Alter Table Operations

This section covers the ALTER TABLE Statement in SQL, detailing how to modify existing table structures by adding, dropping, or changing columns and constraints.

Drop Table Statement

The DROP TABLE statement is used to remove an existing table and its data from a database.

Data Manipulation Language (Dml)

The Data Manipulation Language (DML) facilitates the management and manipulation of actual data stored in database tables through key commands.

Insert Statements

The INSERT statement is essential for adding new rows of data to existing database tables.

Select Statement: Basic Queries

The SELECT statement is a fundamental SQL command used for retrieving data from one or more database tables.

Update Statements

The UPDATE statement in SQL is used to modify existing data within a table.

Delete Statements

The DELETE statement in SQL is used to remove records from a database table based on specified conditions.

Basic Sql Data Types

This section introduces the basic SQL data types used for defining the types of values that can be stored in database columns, including numeric, string, date/time, and boolean types.

Module Summary

This module introduces Structured Query Language (SQL) and covers the fundamental commands for defining database structures and manipulating data.