I'm used to Microsoft SQL Server, where the last SELECT query of a stored procedure determines what is returned.
In Oracle, I'm always using a SYS_REFCURSOR OUT parameter to return data from queries.
Are there other options of returning data from SELECT queries in Oracle stored procedures?
How about SELECT queries that select only one row? Is a SYS_REFCURSOR still necessary?
EDIT: I need to know the answer for Oracle 11g R2 (should have mentioned that explicitly instead of just in the tags).
Until now Oracle has not supported the SQL Server style of procedures implicitly returning a result set, you have had to explicitly return something - which could be a SYS_REFCURSOR or a collection or whatever.
In Oracle 12C a new feature has been added called Implicit Statement Results, which is designed to emulate the SQL Server way of working. However, this is really intended to support migration of existing code from SQL Server; for fresh Oracle development you would be best advised to learn the way Oracle normally does things.
Oracle PL/SQL Procedures can return all the supported basic datattype( date,varchar2,number) plus complex ( records, tables, varray)
Another option is the pipelined function, in which you call the function as:
select ...
from table(my_function(param1 => 1, ...))
See docs for details.
Just for clarifying, ORACLE procedures cannot 'RETURN" per se, a SYS_REFCURSOR OUT parameter is more like changing the value of a variable reference inside the procedure.
Apart from SYS_REFCURSOR, if you are returning only one row of a table, say EMPLOYEE, you can also define a record as EMPLOYEE%ROWTYPE and use it as a OUT type.
Or like:
PROCEDURE pr_proc (v_input in number
v_emp_row out EMPLOYEE%ROWTYPE )
IS
Related
First of all usually I am working with MSSQL. But I have a stored procedure in MSSQL, which I need to use in Oracle now and since I am absolutely new to Oracle I have no idea at all how to do it correct.
I needed to use user defined table types in my MS SQL stored procedure because I am using "logical" tables in my stored procedure, which I also need to pass them to a dynamic sql statement within this procedure (using column names of "physical" tables as variables/parameters).
I've started to add the oracle function in a package I made before for another function. It looks like
TYPE resultRec IS RECORD
(
[result columns]
);
TYPE resultTable IS TABLE OF resultRec;
Function MyFunctionName([A LOT PARAMETERS]) RETURN resultTable PIPELINED;
I also described the layout of the tables (the user defined table types in MSSQL), which I want to use within this function in this package header.
So far so good, but now I don't really know where I have to declare my table variables or user defined table types. I also tried to put them in the package header, but if I am trying to use these tables in the package body, where I am describing my function, Oracle tells met, that the table or view does not exist.
I also tried it to describe the tables within the package body or in the block of my function, which looks like that:
FUNCTION MyFunctionName
(
[MyParameters]
)
RETURN resultTable PIPELINED is rec resultrec;
TYPE tableVariableA IS TABLE OF tableRecA;
TYPE tableVariableB IS TABLE OF tableRecB;
BEGIN
INSERT INTO tableVariableA
SELECT ColumnA, ColumnB FROM physicalTable WHERE[...];
[A LOT MORE TO DO...]
END;
But in this case Oracle also tells me, that it doesn't know the table or view.
I also tried a few more things, but at the end I wasn't able to tell Oracle what table it should use...
I would appreciate every hint, which helps me to understand how oracle works in this case. Thanks a lot!
You can't insert into a collection (e.g. PL/SQL table). You can use the bulk collect syntax to populate the collection:
SELECT ColumnA, ColumnB
BULK COLLECT INTO tableVariableA
FROM physicalTable
WHERE [...];
However, you might want to check this is an appropriate approach, since SQL Server and Oracle differ quite a bit. You can't use PL/SQL tables in plain SQL (at least prior to 12c), even inside your procedure, so you might need a schema-level type rather than a PL/SQL type, but it depends what you will do next. You might not really want a collection at all. Trying to convert T-SQL straight to PL/SQL without understanding the differences could lead you down a wrong path - make sure you understand the actual requirement and then find the best Oracle mechanism for that.
I'm using SQL Oracle to build a stored procedure. I'm trying to build a stored procedure of the SQL-query below.And I want to return those data to a C# program.
select * from employee_master
I have tried following. Is this correct?
CREATE OR REPLACE PROCEDURE EMPLOYEE_SELECTALL (p_recordset OUTSYS_REFCURSOR)AS
BEGIN
OPEN p_recordset FOR
SELECT
*
FROM
EMPLOYEE_MASTER;
END EMPLOYEE_SELECTALL;
If you wish to build a stored procedure that return such resultset first of all you should check if you really need to do this. It's incidental and not recommended way for Oracle. But if you really need so, you should use REF CURSOR.
after executing your stored procedure in SQL Developer, it automatically brings back any output for you to view, including one or more ref cursors.
Example code and screenshots here
I have an oracle stored procedure that accepts a value list through ref cursor. This oracle database is set up as a Linked Server in a separate SQL Server 2008 instance.
How can I use this procedure from within SQL, passing a table, rows, or a table-valued parameter?
I know this question was asked long ago, but for people Googling and come across this post...
It sounds like you need to do a openquery.
This basically sends the 'select...' part (could be a stored procedure exec) command to the linked server and waits for the response.
SELECT * FROM OPENQUERY(Your_Linked_Server_Name , 'select * from TableName where RecordID = 4')
We have an application written in Delphi 2010 which connects to SQL Server Database. Now we're in the process of migrating to Oracle. With SQL Server it was very easy to perform insert, update, delete right from a dbgrid connected to a Stored Procedure.
It's because stored procedures in SQL Server can easily act as a table so that you can do any operation on it, providing it returns the necessary columns within the resultset. Now with Oracle I don't know how do do it. I connect a DBGrid to a DataSource, dataset of which is a Stored Procedure object,but I can't edit the grid. Just Select is possible.
What do I have to do to to achieve this?I use UniDac component suite to connect to Oracle database.
Oracle does not support such functionality. IOW, in Oracle you cannot edit result set provided by a stored procedure or include stored procedure into INSERT INTO <name>, UPDATE <name> or DELETE FROM <name>.
While it is traditional for SQL Server developers to "always" use stored procedures (due to many reasons), it is not traditional for Oracle developers. But it is possible with Oracle too. Search for "REF CURSOR" to see how to fetch data using SP. And use normal or packaged (preferred) SP to post updates to a DB. These procedure will receive old / new field values through arguments.
I cannot say precisely about UniDAC, I can say about AnyDAC. But I will expect UniDAC has similar functionality. To use SP for posting updates you will need to use TXxxUpdateSQL component.
OK,here I'm answering the question though I can see very few are dealing with Delphi recently. Let's say we have a stored proc in Oracle database:
CREATE OR REPLACE PROCEDURE GET_EMPLOYEES
(V_CUR IN OUT SYS_REFCURSOR)
AS
BEGIN
OPEN V_CUR FOR SELECT * FROM EMPLOYEES;
END GET_EMPLOYEES;
Now, in Delphi you pick a stored procedure component (probably from ODAC or UniDac component suite).Set its StoredProcName GET_EMPLOYEES. Then you can add all the fields that the procedure returns in a cursor.If you run the application and activate the stored procedure you'll be able to see all the records. But if you try to insert, modify or delete anything you'll fail to do so. Now, there's a very tricky thing. If you check, you'll see that ReadOnly property of all fields are set to True. Even after you set them to False nothing will change in the real database, although you can edit the DBGrid.
So, we've come to the main part. How did the old Delphi-SQL Server partnership work so that you could do any operation right from a DBGrid? Well, we must understand that there's no magic. If it's SQL, then SQL has only one way of INSERTING,UPDATING and DELETING records-it's with the appropriate SQL statements.With Delphi-SQL Server there seems to be an implicit SQL statement that we never paid attention. But with Oracle, we have to provide our own statements for each operation.
If you use UniDac or ODAC then there's SQLInsert,SQLUpdate,SQLDelete properties in a StoredProc object.If you want to insert a record through DBGrid, then you should edit its SQLInsert property to
INSERT INTO EMPLOYEES VALUES(:EMPLOYEEID,:EMPLOYEENAME)
where variables following : are corresponding to te fields of the stored procedure.They're simply bind variales.When updating and deleting though you'll need some unique value to represent a specific record. Primary key is one option(maybe the only option as I haven't been able to figure out how to use ROWID for the same purpose).So the sql statements for UPDATE and DELETE would be
DELETE FROM EMPLOYEES WHERE EMPLOYEEID=:EMPLOYEEID
and
UPDATE EMPLOYEES SET EMPLOYEENAME=:EMPLOYEENAME WHERE EMPLOYEEID=:EMPLOYEEID
P.S. I just found a way to use ROWID for update and delete statements. In your stored procedure if you choose ROWID too and give it an alias then you can construct your UPDATE and DELETE Statements like such:
UPDATE EMPLOYEES SET EMPLOYEENAME=:EMPLOYEENAME,..... WHERE ROWID=:RECORD_ROWID
DELETE FROM EMPLOYEES WHERE ROWID=:RECORD_ROWID
In the preceding statements RECORD_ROWID is the fieldname returned from stored procedure as a result of aliasing ROWID. If you use :ROWID instead you'll get "ORA-01745: invalid host/bind variable name" error. This is because in a binding variable a colon cannot be followed by a reserved word. And ROWID is a reserved word.
I have two schemas: A and B (Oracle 9). At the A there is a dblink to B. At the B there is a package, that i calls from A. Procedures in B package can returns varying count results and i think that returning a collection is a better way for this reason.
create type B.tr_rad as object (
name varchar2(64)
,code number
,vendor number
,val varchar2(255)
,num number
);
create type B.tt_rad as varray(256) of B.tr_rad;
But from A scheme I cannot use tt_rad type because using SQL-types by dblink is not supported. DBMS_SQL is not supported cursors. Create types with same OID is impossible.
I think to use temporary tables. But firstly it is not that good (after the remote function returns the value, calling side must select collection from remote table). And there are fears of a slowdown of work with temporary tables.
Maybe who knows the alternative interaction?
I've had similar problems in the past. Then I came to the conclusion that fundamentally Oracle's db links are "broken" for anything but simple SQL types (especially UDT's, CLOBS may have problems, XMLType may as well). If you can get the OID solution working then good luck to you.
The solution I resorted to was to use a Java Stored procedure, instead of the DB Link.
Characteristics of the Java Stored Procedure:
Can return a "rich set of types", just about all of the complex types (UDT's, tables/arrays/varrays) see Oracle online documentation for details. Oracle does a much better job of marshalling complex (or rich) types from java, than from a DBLink.
Stored Java can acquire the "default connection" (runs in the same session as the SQL connection to the db - no authentication issues).
Stored Java calls the PL/SQL proc on the remote DB, and the java JDBC layer does the marshaling from the remote DB.
Stored Java packages up the result and returns the results to the SQL or PL/SQL layer.
It's a bit of work, but if you have a bit of java, you should be able to "cut and paste" a solution together from the Oracle documentation and sample.
I hope this helps.
See this existing discussion
referencing oracle user defined types over dblink
An alternative interaction is to have one database with schemas A and B instead of two databases with a database link.
My solution.
On the side B i create temporary table like the collection record. At the A side i have a DBMS_SQL wrapper that calls procedure over dblink. This procedure writes result collection in the temporary table. After successful completion remote procedure i select results from remote temporary table and transform it to local collection type.
Limitations
1. the need for permanent object synchronization.
2. impossibility use A-side procedure (that call remote procedure) in SQL query.
3. the complexity of using.