Using Object Types in Oracle to Return Multiple Tables from a Function
Introduction
In this article, we will explore how to use object types in Oracle to return multiple tables from a function. We will also dive into the details of creating and using an object type in a stored procedure.
Background
Oracle has been supporting the concept of object types for over two decades now. These types can contain values of different data types, including other objects such as tables and records. One of the key features of Oracle’s object types is their ability to return multiple tables from a function or stored procedure.
Creating an Object Type
To create an object type that returns multiple tables, we first need to define the structure of our object type. In this case, let’s create an object type called test_type
that contains two fields: conid
and cov_lineid
. These fields will be of type sys.odcinumberlist
, which is a table type in Oracle.
CREATE TYPE test_type AS OBJECT (
conid sys.odcinumberlist,
cov_lineid sys.odcinumberlist
)
/
Using the Object Type in a Function
Now that we have created our object type, we can use it in a function to return multiple tables. In this case, let’s create a function called function_name
that takes an id
parameter and returns a value of type test_type
.
CREATE OR REPLACE FUNCTION function_name (id NUMBER) RETURN test_type
AS
res test_type;
BEGIN
SELECT /*+ parallel(64)*/ con_id,cov_lineid
BULK COLLECT INTO res.conid, res.cov_lineid
FROM table_name where sava_id like '%'||id||'%';
RETURN res;
END;
/
Understanding the Code
In this code snippet, we first declare a variable res
of type test_type
. We then use a SQL query to select data from the table_name
and bulk collect it into our res.conid
and res.cov_lineid
fields. Finally, we return the value of res
.
Using Object Types in Oracle
One of the key benefits of using object types in Oracle is their ability to simplify complex database operations. By returning multiple tables from a function or stored procedure, you can reduce the amount of code that needs to be written and make your database operations more efficient.
For example, let’s say we want to return both the conid
and cov_lineid
fields for each row in our table_name
. We could use an object type like this:
CREATE TYPE test_type AS OBJECT (
conid NUMBER,
cov_lineid NUMBER
)
CREATE OR REPLACE FUNCTION function_name (id NUMBER) RETURN test_type
AS
res test_type;
BEGIN
SELECT /*+ parallel(64)*/ con_id,cov_lineid
BULK COLLECT INTO res.conid, res.cov_lineid
FROM table_name where sava_id like '%'||id||'%';
RETURN res;
END;
/
In this example, we declare an object type called test_type
that contains two fields: conid
and cov_lineid
. We then use a SQL query to select data from the table_name
and bulk collect it into our res.conid
and res.cov_lineid
fields. Finally, we return the value of res
.
Handling Null Values
One of the key considerations when using object types in Oracle is how you will handle null values. In this case, let’s say we want to use an object type that contains a null value for either the conid
or cov_lineid
field.
CREATE TYPE test_type AS OBJECT (
conid NUMBER,
cov_lineid NUMBER DEFAULT NULL
)
CREATE OR REPLACE FUNCTION function_name (id NUMBER) RETURN test_type
AS
res test_type;
BEGIN
SELECT /*+ parallel(64)*/ con_id,cov_lineid
BULK COLLECT INTO res.conid, res.cov_lineid
FROM table_name where sava_id like '%'||id||'%';
IF res.conid IS NULL THEN
res.conid := 0;
END IF;
RETURN res;
END;
/
In this example, we declare an object type called test_type
that contains a null value for the cov_lineid
field. We then use a SQL query to select data from the table_name
and bulk collect it into our res.conid
and res.cov_lineid
fields. If the conid
is null, we set it to 0.
Handling Multiple Null Values
Let’s say we want to use an object type that contains multiple null values for either the conid
or cov_lineid
field. In this case, let’s create an object type called test_type
that contains two fields: conid
and cov_lineid
. We then use a SQL query to select data from the table_name
and bulk collect it into our res.conid
and res.cov_lineid
fields.
CREATE TYPE test_type AS OBJECT (
conid sys.odcinumberlist,
cov_lineid sys.odcinumberlist DEFAULT NULL
)
CREATE OR REPLACE FUNCTION function_name (id NUMBER) RETURN test_type
AS
res test_type;
BEGIN
SELECT /*+ parallel(64)*/ con_id,cov_lineid
BULK COLLECT INTO res.conid, res.cov_lineid
FROM table_name where sava_id like '%'||id||'%';
IF res.conid IS NULL THEN
res.conid := sys.odcinumberlist;
END IF;
RETURN res;
END;
/
In this example, we declare an object type called test_type
that contains two fields: conid
and cov_lineid
. We then use a SQL query to select data from the table_name
and bulk collect it into our res.conid
and res.cov_lineid
fields. If the conid
is null, we set it to an empty object type called sys.odcinumberlist
.
Conclusion
Using object types in Oracle can simplify complex database operations and make your code more efficient. By returning multiple tables from a function or stored procedure, you can reduce the amount of code that needs to be written and make your database operations more efficient.
In this article, we explored how to use object types in Oracle to return multiple tables from a function. We also discussed handling null values and multiple null values when using object types.
Last modified on 2024-02-05