REQUEST COMPLIMENTARY SQLS*PLUS LICENCE
Oracle EXTEND method
In Oracle PL/SQL, the EXTEND method is a procedure that adds elements to the end of Varray or Nested Tables. The collection can be empty, but not NULL.
Syntax of EXTEND method in Oracle PL/SQL
collection_name.EXTEND;
collection_name.EXTEND (n);
collection_name.EXTEND (n, i);
Method parameters and arguments
- collection_name – the name of the collection.
- EXTEND – adds one zero element to the collection.
- EXTEND (n) – adds n zero elements to the collection.
- EXTEND (n, i) – adds n copies of the i-th element to the collection.
Note:
- EXTEND (n, i) is the only form you can use for a collection whose elements have a NOT NULL limitation.
- EXTEND works with the internal size of the collection. That is, if DELETE removes an item but saves its filler,
- EXTEND assumes that the item exists.
Let’s look at an example to understand how to use the EXTEND collection method in Oracle PL/SQL:
EXTEND example with Nested Tables
- Consider an example where we declare the Nested Tables variable by initializing it with three elements; we add two copies of the first element;
- remove the fifth (last) element; and then add one zero element.
Since EXTEND believes that the removed fifth element exists, the added zero element is the sixth element. The print_nt procedure prints the Nested Tables variable after initialization and after EXTEND and DELETE operations.
CREATE OR REPLACE TYPE nt_type IS TABLE OF NUMBER;
CREATE OR REPLACE PROCEDURE print_nt (nt nt_type) IS
i NUMBER;
BEGIN
i := nt.FIRST;
IF i IS NULL THEN
DBMS_OUTPUT.PUT_LINE('nt is empty');
ELSE
WHILE i IS NOT NULL LOOP
DBMS_OUTPUT.PUT('nt.(' || i || ') = '); print(nt(i));
i := nt.NEXT(i);
END LOOP;
END IF;
DBMS_OUTPUT.PUT_LINE('---');
END print_nt;
DECLARE
nt nt_type := nt_type(11, 22, 33);
BEGIN
print_nt(nt);
nt.EXTEND(2,1); -- Add two copies of the first element
print_nt(nt);
nt.DELETE(5); -- Remove the fifth element
print_nt(nt);
nt.EXTEND; -- Add one zero element
print_nt(nt);
END;
Result:
nt.(1) = 11
nt.(2) = 22
nt.(3) = 33
---
nt.(1) = 11
nt.(2) = 22
nt.(3) = 33
nt.(4) = 11
nt.(5) = 11
---
nt.(1) = 11
nt.(2) = 22
nt.(3) = 33
nt.(4) = 11
---
nt.(1) = 11
nt.(2) = 22
nt.(3) = 33
nt.(4) = 11
nt.(6) = NULL
---
PL/SQL tutorial: PL/SQL Collection Method EXTEND in Oracle Database
MORE NEWS
PreambleNoSql is not a replacement for SQL databases but is a valid alternative for many situations where standard SQL is not the best approach for...
PreambleMongoDB Conditional operators specify a condition to which the value of the document field shall correspond.Comparison Query Operators $eq...
5 Database management trends impacting database administrationIn the realm of database management systems, moreover half (52%) of your competitors feel...
The data type is defined as the type of data that any column or variable can store in MS SQL Server. What is the data type? When you create any table or...
PreambleMS SQL Server is a client-server architecture. MS SQL Server process starts with the client application sending a query.SQL Server accepts,...
First the basics: what is the master/slave?One database server (“master”) responds and can do anything. A lot of other database servers store copies of all...
PreambleAtom Hopper (based on Apache Abdera) for those who may not know is an open-source project sponsored by Rackspace. Today we will figure out how to...
PreambleMongoDB recently introduced its new aggregation structure. This structure provides a simpler solution for calculating aggregated values rather...
FlexibilityOne of the most advertised features of MongoDB is its flexibility. Flexibility, however, is a double-edged sword. More flexibility means more...
PreambleSQLShell is a cross-platform command-line tool for SQL, similar to psql for PostgreSQL or MySQL command-line tool for MySQL.Why use it?If you...
PreambleWriting an application on top of the framework on top of the driver on top of the database is a bit like a game on the phone: you say “insert...
PreambleOracle Coherence is a distributed cache that is functionally comparable with Memcached. In addition to the basic function of the API cache, it...
PreambleIBM pureXML, a proprietary XML database built on a relational mechanism (designed for puns) that offers both relational ( SQL / XML ) and...
What is PostgreSQL array? In PostgreSQL we can define a column as an array of valid data types. The data type can be built-in, custom or enumerated....
PreambleIf you are a Linux sysadmin or developer, there comes a time when you need to manage an Oracle database that can work in your environment.In this...
PreambleStarting with Microsoft SQL Server 2008, by default, the group of local administrators is no longer added to SQL Server administrators during the...