PL/SQL Quiz on Variables and Conditions

PL/SQL Course

• This course covers PL/SQL, a procedural language extension to SQL
• It includes features of procedural programming to enhance SQL
• SQL statements are embedded within PL/SQL code
• Code is stored in the database and called upon for execution
• Variables and constants, along with conditional statements (IF statements) and loops, are used
• PL/SQL offers modular programming (nested blocks, and libraries for reusability)
• Integration with Oracle products like JDeveloper
• Portability across different operating systems
• Exception handling for error management

Introduction to PL/SQL

• PL/SQL extends SQL with procedural features
• SQL queries can be included within PL/SQL code
• Stored code in databases is directly callable
• PL/SQL enables variable and constant declarations
• Conditional statements (IF-THEN-ELSE) and loops for repetitive tasks
• Code can be written and executed once, then used multiple times
• Modularity, integration, portability and exception handling are features of PL/SQL
• It's implemented within Oracle Database

PL/SQL Block Structure

• Declarative Section: Variable definitions, cursors
• Executable Section: SQL statements, PL/SQL statements
• Exception Section: Error handling
• Each block requires BEGIN and END keywords
• Variables, cursors and constants are optional aspects of declaration
• SQL and PL/SQL statements are located here
• Exception handling can be done here

PL/SQL Block Types

• Anonymous Block: A block without a name, executed where defined
• Subprograms: Blocks that accept parameters, stored in databases (procedures and functions)

Writing Executable Statements

• Single-line comments begin with "--"
• Multi-line comments start with "/" and end with "/"
• Comments improve code readability and maintainability
• PL/SQL supports SQL functions (e.g., decode, group functions) for use within blocks

SQL Functions in PL/SQL

• Integration of SQL functions into PL/SQL code using the syntax: InitCap(String) for example
• Example calls include InitCap('king')

Nested Blocks

• Inner blocks can access variables in outer blocks, but outer blocks cannot access variables in inner blocks directly
• Sub-block can have own declaration or values for same variables as outer block.

Operators in PL/SQL

• Similar to SQL, PL/SQL supports logical, arithmetic and concatenation operators
• Parentheses dictate order of operations
• Qualifiers are used to refer to particular variables, so that variables with same names from different blocks are not confused. (outer vs inner blocks)

Interacting with the Oracle Server

• Data manipulation statements (INSERT, UPDATE, DELETE) are supported
• SQL statements are executed through PL/SQL.

SQL Cursors (Implicit and Explicit)

• Implicit cursors: implicitly declared and managed by Oracle for SQL statements
• Explicit cursors: declared and managed by the programmer for greater control and to handle data efficiently

Handling Exceptions

• Predefined exceptions: Oracle-provided error messages
• User-defined exceptions: programmer-defined error messages for better presentation of errors
• PL/SQL code provides an Exception handling section where errors can be managed and handled by programmer

PL/SQL Program Units

• Stored Procedures: Reusable code blocks for executing more complex operations
• Stored Functions: Reusable blocks that return a value

Working with Composite Data Types

• Records: complex data structures with multiple fields
• Collections (Index-By Tables, Nested Tables, and Varrays): organize multiple related values

PL/SQL Collections

• Index-By Tables: collections with named indexes for efficient access to elements
• Nested Tables: collections with similar data types, stored within other data structures
• Varrays: collections with fixed size and better performance for homogeneous data types

Using PL/SQL Collections with Index-By Tables and other Types

• Using PL/SQL collections, such as Index-by Tables and other type, within the code

Creating Packages

• Packages: Bundles of procedures, functions, and variables for enhanced code organization and reuse

Viewing PL/SQL Objects in Data Dictionary

• Tools for viewing and examining PL/SQL objects (procedures, functions, and packages) saved in the database

More Package Concepts and Overloading

• Package overloading: allows using the same name for multiple subprograms (procedures or functions) within a package, differentiating them through parameter counts or parameter types

PL/SQL Procedures and Functions with Parameters

• Procedures and Functions: reusable blocks of PL/SQL code that can accept parameters
• Parameters can be passed as IN, OUT, or IN OUT, defining how they are used in procedures

Pass by Value, Pass by Reference; IN, OUT, IN OUT parameters

• IN, OUT, IN OUT are used to define how parameters are used in procedures
• Using Positional notation, Named notation, or Combination notation for passing parameters

Forward Declarations

• Necessary if procedures or functions are used before they are defined in the code

Contact Information

• Contact information for the course instructor is included