Book Image

The SQL Workshop

By : Frank Solomon, Prashanth Jayaram, Awni Al Saqqa
Book Image

The SQL Workshop

By: Frank Solomon, Prashanth Jayaram, Awni Al Saqqa

Overview of this book

Many software applications are backed by powerful relational database systems, meaning that the skills to be able to maintain a SQL database and reliably retrieve data are in high demand. With its simple syntax and effective data manipulation capabilities, SQL enables you to manage relational databases with ease. The SQL Workshop will help you progress from basic to advanced-level SQL queries in order to create and manage databases successfully. This Workshop begins with an introduction to basic CRUD commands and gives you an overview of the different data types in SQL. You'll use commands for narrowing down the search results within a database and learn about data retrieval from single and multiple tables in a single query. As you advance, you'll use aggregate functions to perform calculations on a set of values, and implement process automation using stored procedures, functions, and triggers. Finally, you'll secure your database against potential threats and use access control to keep your data safe. Throughout this Workshop, you'll use your skills on a realistic database for an online shop, preparing you for solving data problems in the real world. By the end of this book, you'll have built the knowledge, skills and confidence to creatively solve real-world data problems with SQL.
Table of Contents (13 chapters)

Types of Data Integrity

Let's look at the different types of data integrity:

  • Entity integrity: This defines each row as unique within the table. No two rows can have the same name. To achieve this, a primary key can be defined. This field contains a unique identifier—no two rows can contain the same unique identifier.
  • Referential integrity: Referential integrity is about relationships. When two or more tables have a relationship, we must ensure that the value of the foreign key always matches the value of the primary key, otherwise the record is orphaned.

    Referential integrity prevents adding records to a related table if there is no associated record in the primary or parent table, changing values in a primary table that can result in orphaned records in a related table, and deleting records from a primary table if there are matching related records.

  • Domain integrity: This is primarily concerned with the validity of entries for a given column. It is important...