Where do we declare PL SQL?

PL/SQL variables must be declared in the declaration section or in a package as a global variable. When you declare a variable, PL/SQL allocates memory for the variable’s value and the storage location is identified by the variable name.

Where do we use PL SQL?

PL/SQL gives high productivity to programmers as it can query, transform, and update data in a database. PL/SQL saves time on design and debugging by strong features, such as exception handling, encapsulation, data hiding, and object-oriented data types. Applications written in PL/SQL are fully portable.

Where do you declare a cursor in PL SQL language?

An explicit cursor should be defined in the declaration section of the PL/SQL Block. It is created on a SELECT Statement which returns more than one row.

How do you declare a variable in Oracle?

Oracle / PLSQL: Declaring Variables

  1. Syntax. The syntax for declaring variables in Oracle is: variable_name [CONSTANT] datatype [NOT NULL] [:= | DEFAULT initial_value] …
  2. Example – Declaring a variable. …
  3. Example – Declaring a variable with an initial value (not a constant) …
  4. Example – Declaring a constant.
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How do you declare a procedure identifier?

Following are the commonly used naming conventions in PL/SQL:

  1. The first letter should be used to specify the declared level of the variable. The below point give the different first letters and their declarative level.
  2. ‘P’ – Variable is declared at the parameter level. …
  3. The second letter specifies the type of identifier.

What are the disadvantages of PL SQL?

Disadvantages of using PL/SQL

  • The debugger never worked.
  • Ant syntax error is just reported by a general error message. Without any. indication for its location. The only way to find it is to comment out parts. …
  • The syntax is awkward, complex and inconsistent.

Is PL SQL better than SQL?

Procedural language capability: It consists of procedural language constructs like conditional statements (if else statements) and loops like (FOR loops). Better performance: PL/SQL engine processes multiple SQL statements at the same time as one block, thereby reducing network traffic.

How do I create a trigger in PL SQL?

Syntax for creating trigger:

  1. CREATE [OR REPLACE ] TRIGGER trigger_name.
  2. {BEFORE | AFTER | INSTEAD OF }
  3. {INSERT [OR] | UPDATE [OR] | DELETE}
  4. [OF col_name]
  5. ON table_name.
  6. [REFERENCING OLD AS o NEW AS n]
  7. [FOR EACH ROW]
  8. WHEN (condition)

What is trigger in PL SQL with examples?

Triggers are stored programs, which are automatically executed or fired when some events occur. Triggers are, in fact, written to be executed in response to any of the following events − A database manipulation (DML) statement (DELETE, INSERT, or UPDATE) A database definition (DDL) statement (CREATE, ALTER, or DROP).

Which type of cursor is automatically declared?

21) Which type of cursor is automatically declared by Oracle every time an SQL statement is executed? Explanation: The implicit cursor are automatically created.

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How do you declare a local variable in PL SQL?

Let’s take an example to show the usage of Local and Global variables in its simple form:

  1. DECLARE.
  2. — Global variables.
  3. num1 number := 95;
  4. num2 number := 85;
  5. BEGIN.
  6. dbms_output. put_line(‘Outer Variable num1: ‘ || num1);
  7. dbms_output. put_line(‘Outer Variable num2: ‘ || num2);
  8. DECLARE.

How do you declare a procedure?

Procedures that take no parameters are written without parentheses. The procedure body begins with the keyword IS (or AS ) and ends with the keyword END followed by an optional procedure name. The procedure body has three parts: an optional declarative part, an executable part, and an optional exception-handling part.

How do you declare a date variable in PL SQL?

DECLARE startDate DATE := to_date(’03/11/2011′, ‘dd/mm/yyyy’); reccount INTEGER; BEGIN SELECT count(*) INTO reccount FROM my_table tab WHERE tab. somedate < startDate; dbms_output. put_line(reccount); END; You can also use the DEFINE statement to use simple string substitution variables.

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