Using EXISTS

The EXISTS(n) returns TRUE if the nth element in a collection exist. Or else, EXISTS(n) returns FALSE. Primarily, you use EXISTS with DELETE to maintain the sparse nested tables. You can also use EXISTS to avoid raising an exception whenever you reference a nonexistent element. In the example below, the PL/SQL executes the assignment statement only if the element i exists:

IF courses.EXISTS(i) THEN courses(i) := new_course; END IF;

When passed an out-of-range subscript, the EXISTS returns FALSE instead of raising SUBSCRIPT_OUTSIDE_LIMIT.

Posted Date: 10/4/2012 3:13:06 AM | Location : United States

Ask an Expert

Related Discussions:- Using exists - collection methods, Assignment Help, Ask Question on Using exists - collection methods, Get Answer, Expert's Help, Using exists - collection methods Discussions

Write discussion on Using exists - collection methods
Your posts are moderated

Write your message here..

Related Questions

Disjunction - sql, Disjunction (OR, ∨) Again we have nine rows instead... Disjunction (OR, ∨) Again we have nine rows instead of just four and again, when unknown is not involved, the rows are as for 2VL. Also, when anything is paired with true, t

When are constraints checked - sql, When Are Constraints Checked Unde... When Are Constraints Checked Under the model constraints are conceptually checked at all statement boundaries (and only at statement boundaries). By default the same is true

Parameter and keyword description - packages, Parameter and Keyword Descrip... Parameter and Keyword Description: package_name: This construct identifies the package. AUTHID Clause: This determine whether all the packaged subprograms impleme

Using not null-declarations in sql, Using NOT NULL Besides assigning an ... Using NOT NULL Besides assigning an initial value, the declarations can impose the NOT NULL constraint, as the example below shows: acct_id INTEGER(4) NOT NULL := 9999; You ca

Why use cursor variables, Why Use Cursor Variables ? Primarily, you use... Why Use Cursor Variables ? Primarily, you use the cursor variables to pass the query result sets between the PL/SQL stored subprograms and different clients. Neither PL/SQL nor

Relational operators and logical operators, Relational Operators and Logica... Relational Operators and Logical Operators It prepares the ground for subsequent sections in which each specific relational operator is paired with its logical counterpart, su

Using limit - collection method, Using LIMIT For nested tables, that h... Using LIMIT For nested tables, that have no maximum size, the LIMIT returns NULL. For varrays, the LIMIT returns the maximum number of elements that a varray can have (that yo

Example of groupby operator - sql, Example of GROUPBY Operator Example... Example of GROUPBY Operator Example: How many students sat each exam, using GROUP BY, NATURAL LEFT JOIN, and COALESCE SELECT CourseId, COALESCE (n, 0) AS n FROM COURS

Procedure, 1. Create a procedure called TAX_COST_SP to accomplish the tax c... 1. Create a procedure called TAX_COST_SP to accomplish the tax calculation task. Keep in mind that the state and subtotal values are inputs into the procedure and the procedure is

Using savepoints, Using Savepoints The scope of the savepoint is a tra... Using Savepoints The scope of the savepoint is a transaction in which it is defined. The Savepoints defined in the major transaction are not related to the savepoints defined