PL/SQL: What is cursor and what is use of it?

As a registered tutor on UrbanPro.com specializing in PL/SQL Training, I'm here to provide you with a comprehensive understanding of Cursors in PL/SQL.

Understanding Cursors in PL/SQL

Introduction to Cursors

In PL/SQL, a cursor is a temporary work area created in the system memory when a SQL statement is executed. It allows the retrieval of one or more rows of data from the result set of a query.

Types of Cursors

1. Implicit Cursors:

   • Automatically created by PL/SQL for every SQL statement.
   • Used for queries where the number of rows returned is known at compile-time.

2. Explicit Cursors:

   • Defined by the programmer.
   • Used for queries where the number of rows returned is unknown at compile-time.

Key Components of Cursors

1. Declaration:

   • Cursors must be declared before using them.
   • Syntax: CURSOR cursor_name IS SELECT statement;

2. Opening a Cursor:

   • Once declared, a cursor must be opened before fetching data.
   • Syntax: OPEN cursor_name;

3. Fetching Data:

   • Retrieves one or more rows from the result set.
   • Syntax: FETCH cursor_name INTO variable;

4. Closing a Cursor:

   • After fetching data, the cursor should be closed to release resources.
   • Syntax: CLOSE cursor_name;

Use Cases of Cursors in PL/SQL

1. Processing Rows Individually:

   • Cursors allow processing of query results row by row, enabling individual manipulation.

2. Dynamic SQL Execution:

   • Cursors are essential for executing dynamic SQL statements whose structure is determined at runtime.

3. Multiple Row Operations:

   • Cursors facilitate handling queries that return multiple rows, enabling effective data manipulation.

4. Data Validation and Transformation:

   • Cursors are useful for validating and transforming data before presenting it to the user or storing it in a database.

Best Online Coaching for PL/SQL Training

If you are seeking the best online coaching for PL/SQL Training, consider the following factors:

1. Experienced Tutors:

   • Look for tutors with extensive experience in PL/SQL development and training.

2. Comprehensive Course Content:

   • Ensure the training program covers all essential aspects of PL/SQL, including in-depth coverage of cursors.

3. Interactive Learning:

   • Opt for courses that provide hands-on exercises and real-world scenarios to enhance practical skills.

4. Student Reviews and Ratings:

   • Check reviews and ratings from previous students to gauge the effectiveness of the course.

By considering these factors, you can find the most suitable online coaching for PL/SQL Training that includes a thorough understanding of Cursors and their practical applications.