In this PL/SQL tutorial, you will learn the basic concepts of this procedural language. The language is block structured and supports nested loops and logical operators. Moreover, this tutorial will help you write SQL statements to query data from databases. Once you understand this fundamental language, you can quickly register your programs.
PL/SQL is a procedural language.
PL/SQL is an extension of SQL, a standard database language that adds procedural capabilities. While SQL has no loops, PL/SQL supports them and provides additional features such as encapsulation, functions, packages, and triggers. It can also act as an application language.
PL/SQL makes it easy to detect and process errors. When errors occur, the language automatically raises an exception, which transfers control to unique exception-handling code. The exception handlers process each exception. In addition, PL/SQL supports composite data structures and passing related items to subprograms.
PL/SQL is often used to build and maintain applications, including user screens, formatted pages, and database applications. Its high-speed execution speed makes it the preferred choice for web development. In contrast to SQL, PL/SQL allows for multiple operations at once, which makes it a better choice for building server-side applications.
SQL is a high-level language that offers greater abstraction than procedural languages. This allows portability and ends users to work with different database management systems. The language consists of blocks of code, which are nested and represent a task. The PL/SQL code is often stored within an info file in a database. PL/SQL allquickly ows users to modify the data stored abase quickly.
It is a block structure language.
Block structure languages use the structure of a block of code to represent business logic. Partnerships are often written in a reusable style and may include repetitive code execution and conditional execution. For example, Oracle databases use PL/SQL blocks for reusing business logic.
PL/SQL blocks consist of three parts: a declaration part, an execution part, and an exception-handling claim. The execution part should contain executable PL/SQL statements. There can also be nested blocks within a block. A block starts with the keyword ‘BEGIN’ and ends with the keyword ‘END’.
A block in PL/SQL consists of a declaration section, an execution section, and an exception handling section. In PL/SQL, the execution block contains the business logic. This block may involve several data manipulations and retrievals from a database. If a named block is used, it can be called multiple times, whereas anonymous blocks are only executed once.
PL/SQL allows programmers to declare constants and variables. These variables can be changed during the program execution. A cursor also contains attributes that provide information about its state. Another type of variable is a composite variable. These variables have internal components and can be passed to a subprogram as a parameter.
It supports logical operators.
The logical operators in PL/SQL allow you to make comparisons based on Boolean operands. They can be used in conditional control statements. For example, you can use the NOT operator to negate the result of a comparison. You can also use the AND operator to link multiple comparisons.
It supports nested loops.
In PL/SQL, you can use loops to repeat the same sequence of statements. You can also place circles inside other circles. The following examples show how you can do this. Nesting a loop means that the loop will refer to the outer loop’s counter.
Oracle 11g supports nested loops and prefetching, which makes nested loops appear as children of a table access operation. This allows the database to prioritize the ROWIDs used by the circle. This feature is useful when nested loops contain consecutive ROWIDs. It also allows you to use multi-block reads on the nested loop.
If you have more than one ELSIF condition in your query, you can combine them into a single one. The ELSIF condition is equivalent to an IF-THEN-ELSIF statement. It executes all the statements associated with that condition. If it returns TRUE, PL/SQL then skips ahead to the END IF statement list. If it is false or NULL, the loop executes the corresponding statement list in the following IF-THEN-ELSE clause.