SQL

SQL Overview Select Statement

SQL Overview

For this tutorial, we will focus only on Oracle SQL. But understanding Oracle SQL means you already understanding other kinds of SQL by over 90 percent.

  1. Overview of Database Concepts

    • A database is organized data that can be easily accessed, managed, and updated. The structure enables users to create, read, update, and delete data efficiently.
    • Types of databases include hierarchical, network, relational (the most common), and non-relational (NoSQL).

  2. Introduction to Relational Databases

    • Relational databases are structured to recognize relations between stored items of information. They use tables, which consist of rows and columns.

  3. Oracle Database Architecture Overview

    • Oracle Database architecture includes components like the Instance (memory structures and background processes) and the Database (data files, control files).

SQL Overview

  1. What is SQL?

    • SQL (Structured Query Language) is the standard language used for interacting with relational databases. It allows users to perform tasks like querying data, updating records, and managing database structures.

  2. Types of SQL: DDL, DML, DCL, and TCL

    • DDL (Data Definition Language): Used to define database structures. Examples: CREATE, ALTER, DROP.
    • DML (Data Manipulation Language): Used to manipulate data. Examples: SELECT, INSERT, UPDATE, DELETE.
    • DCL (Data Control Language): Used for access control. Examples: GRANT, REVOKE.
    • TCL (Transaction Control Language): Used to manage transactions. Examples: COMMIT, ROLLBACK.

  3. SQL Standards and Compatibility

    • SQL has various standards defined by ANSI and ISO. Oracle extends SQL with PL/SQL (Procedural Language/SQL), a rich procedural language.

Setting Up the Environment

  1. Installing Oracle Database 19c

    • Follow the installation guide provided by Oracle to install Oracle Database 19c. Set up environment variables and configure database settings as needed.

  2. Introduction to SQL Developer

    • SQL Developer is a free graphical interface to Oracle Database. It allows users to run SQL queries, browse database objects, and manage them.