What is the function of the PL?

Function. The purpose of a PL/SQL function is generally used to compute and return a single value. This returned value may be a single scalar value (such as a number, date or character string) or a single collection (such as a nested table or array).

What is a PL test?

Photoluminescence spectroscopy, often referred to as PL, is when light energy, or photons, stimulate the emission of a photon from any matter. It is a non-contact, nondestructive method of probing materials. … The emission of light or luminescence through this process is photoluminescence, PL.

What is a public procedure?

Public Procedures:

Any procedures declared inside the package specification are visible outside the package and can be accessed in any objects.

What are Plsql functions?

The PL/SQL Function is very similar to PL/SQL Procedure. The main difference between procedure and a function is, a function must always return a value, and on the other hand a procedure may or may not return a value.

What are triggers in Plsql?

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).

What is public and private procedures in PL SQL?

Public and Private Data and Procedures

You can define the package so that only three procedures are public and therefore available for execution by a user of the package; the remainder of the procedures are private and can only be accessed by the procedures within the package.

What do you think is the different between a private and a public procedure?

Public vs. Private. The terms Public and Private are used in relation to Modules. The basic concept is that Public variables, subs or functions can be seen and used by all modules in the workbook while Private variables, subs and functions can only be used by code within the same module.

How do you call a sub in Visual Basic?

Calling a Sub Procedure

You call a Sub procedure by using the procedure name in a statement and then following that name with its argument list in parentheses. You can omit the parentheses only if you don’t supply any arguments. However, your code is more readable if you always include the parentheses.

What is the difference between package and trigger in PL SQL?

Stored procedures can be invoked explicitly by the user. It’s like a java program , it can take some input as a parameter then can do some processing and can return values. On the other hand, trigger is a stored procedure that runs automatically when various events happen (eg update, insert, delete).

What is a package in PL SQL?

In PL/SQL, a package is a schema object that contains definitions for a group of related functionalities. A package includes variables, constants, cursors, exceptions, procedures, functions, and subprograms. It is compiled and stored in the Oracle Database. Typically, a package has a specification and a body.

What are the advantages and disadvantages of PL SQL?

Advantage of Using PL/SQL
  • Better performance, as SQL is executed in bulk rather than a single statement.
  • High Productivity.
  • Tight integration with SQL.
  • Full Portability.
  • Tight Security.
  • Support Object Oriented Programming concepts.

What is the difference between PL SQL and SQL?

There are many differences between SQL and PL/SQL. SQL is a non-procedural language that executes a single query at a time whereas, PL/SQL is a procedural language and executes blocks of code at once which helps reduce traffic and increases processing speed.

What is the requirement to use PL SQL?

System requirements

x, 8i, 9i, 10g, 11g, 12c, 18c and 19c on any platform. To connect to an Oracle database, the 32 bit PL/SQL Developer version requires a 32 bit Oracle Client and the 64 bit PL/SQL Developer version requires a 64 bit Oracle Client.

What is the purpose of triggers?

Triggers are used to maintain the referential integrity of data by changing the data in a systematic fashion. Each trigger is attached to a single, specified table in the database. Triggers can be viewed as similar to stored procedures in that both consist of procedural logic that is stored at the database level.

What is the basic structure of PL SQL?

PL/SQL is a block-structured language whose code is organized into blocks. A PL/SQL block consists of three sections: declaration, executable, and exception-handling sections. In a block, the executable section is mandatory while the declaration and exception-handling sections are optional. A PL/SQL block has a name.

Why do we need stored procedures?

A stored procedure provides an important layer of security between the user interface and the database. It supports security through data access controls because end users may enter or change data, but do not write procedures. … It improves productivity because statements in a stored procedure only must be written once.

Can triggers be enabled or disabled?

Triggers can be re-enabled by using ENABLE TRIGGER. DML triggers defined on tables can be also be disabled or enabled by using ALTER TABLE. Changing the trigger by using the ALTER TRIGGER statement enables the trigger.

What does PK mean in database?

Primary key (PK) – value which uniquely identifies every row in the table. Foreign keys (FK) – values match a primary or alternate key inherited from some other table. Alternate Keys (AK) – key associated with one or more columns whose values uniquely identify every row in the table, but which is not the primary key.

How many times trigger statement executed?

3 Answers. It all depends on the type of trigger you are using. a statement level trigger will fire once for the whole statement.

Are views stored in memory?

The view is a query stored in the data dictionary, on which the user can query just like they do on tables. It does not use the physical memory, only the query is stored in the data dictionary. It is computed dynamically, whenever the user performs any query on it.

What happens when a trigger is disabled MCQs?

Point out the wrong statement:

AFTER triggers cause their source DML operation to skip.

What is the syntax for disabling a trigger?

You can subsequently disable the trigger with the following statement: ALTER TRIGGER update_job_history DISABLE; When the trigger is disabled, the database does not fire the trigger when an UPDATE statement changes an employee’s job.