Job Ready SQL

Lesson 9Applying CRUD: Basic Data Management and Manipulation

In lesson 7, “Database Management Using DDL”, you learned how to create a database and set up the tables. The vast majority of work done in a database, however, involves retrieving and manipulating the data itself. While these tasks often require understanding how the database is structured, most of the people who use a database will never be expected to design a database or create a database structure.

Learning Objectives

By the end of this lesson, you will be able to:

• Create new data within existing tables in a relational database using SQL
• Retrieve existing data from a database
• Update existing data within a relational database
• Delete data from a relational database

DATA MANIPULATION LANGUAGE

In this lesson, four activities involved in working with data will be reviewed. These center on creating, retrieving, updating, and deleting data from a database using SQL. It is common to use the acronym CRUD to refer to these activities.

Before data can be retrieved, it has to be created. In this lesson, the Data Manipulation Language (DML) will specifically be used to show how standard SQL can add data to existing tables, update existing data, and delete data.

REQUIREMENTS As with the previous lesson, you will need MySQL installed and running on your computer to run the examples in this and future lessons.

CREATE A DATABASE

Before DML operations can be performed on a database, the database needs to exist. ...