I'm trying to convert some Informix ESQL to Oracle Pro*C. In the existing Informix code the "SERIAL" data type was used to indicate automatically incrementing columns. According to the Oracle documentation, the Oracle Migration Workbench for Informix should be able to handle this, and it explains that it converts the "SERIAL" data type into a "NUMBER" with an associated Oracle sequence and trigger. However, when trying to run the tool it simply replaces the word "SERIAL" with "ERROR(SERIAL)", so I've been trying to manually add in the trigger/sequence.
Their example here: http://docs.oracle.com/html/B16022_01/ch2.htm#sthref112 shows a way that this can be done. The sequence appears to be fairly straight forward, however when trying to create a trigger like so:
CREATE TRIGGER clerk.TR_SEQ_11_1
BEFORE INSERT ON clerk.JOBS FOR EACH ROW
BEGIN
SELECT clerk.SEQ_11_1.nextval INTO :new.JOB_ID FROM dual; END;
The Pro*C preprocessor picks up the "CREATE" keyword here, and decides that I'm not allowed to use the host variable ":new.JOB_ID", because host variables cannot be used in conjunction with "CREATE" statements.
My question is, is there some way to create a trigger that links an Oracle sequence to a particular column without using a host variable to specify the column name? The Oracle documentation seems to indicate that their migration tool should be able to cope, which means there must be some way of doing this. However all the examples of the trigger use that I have found all use the host variable which causes the preprocessor to complain.
Thank you for your time.
(Note: I've used the trigger/sequence/column names from the example in the Oracle documentation in the example above.)
I managed to resolve the issue by using an "EXEC SQL EXECUTE IMMEDIATE" statement.
char sql_buf[4096+1];
snprintf(sql_buf, 4096, <sql>);
EXEC SQL IMMEDIATE :sql_buf;
This bypasses the preprocessor and therefore allows the statement through without complaint.
It is impossible to create a trigger that links an Oracle sequence to a particular column without using a "host variable" to specify the column name. By the way it isn't "host variable" - just reference. The same trigger may fire on update and insert for example, so you have to specify what you are referencing: new or old variables. You can do it in MS-SQL but not in Oracle.
Related
This question is inspired by this.
As stated, I don't want a solution from PL/SQL. I want a 1 or 2 SQL statements that will check for table existence and if its not exist - create it.
Such statement(s) will be plugged into C++ application (not a script) and so I want a plain SQL solution. If such solution is not exist (please say so), I'd like to have a simple string I can plug into C++ code and use either SQLExecute() or a native Oracle client API to execute such a string.
Trying to google for a solution I am getting a results that can be used either in the shell script or a stored procedure. As I explain here and in the previous question - my situation is completely different - I work in C++ and want an appropriate solution.
There is no single SQL statement that will create a table only if it does not exist in Oracle 11g.
It is not obvious to me why you're objecting to a PL/SQL based solution. If you're using raw ODBC calls in C++, you can pass a PL/SQL block to SQLPrepare just as you would pass a plain SQL statement. Given that PL/SQL blocks work almost exactly like a pure SQL statement, it would be unusual to categorically reject a PL/SQL based solution.
If you are going to categorically reject PL/SQL, you can certainly take the logic from any of the PL/SQL based solutions and implement that in a couple of SQL statement executed from your application. For example, you can query dba_| all_| user_tables (depending on your privileges, whether you are creating tables in other schemas, etc.) to determine whether the table exists and then conditionally execute your DDL
select owner, table_name
from dba_tables
where owner = <<schema that will own the table>
and table_name = <<name of the table>>
If that returns no rows you can then execute your DDL.
Of course, you can also just execute your DDL statement and catch the ORA-00955 name is already used by an existing object error in C++.
I have created a temporary table in oracle sql developer but I forgot to save it and now I want to reuse the query but I don't remember the code used then. Is there a process to get query used creation of temp table?
You can use dbms_metadata.get_ddl()
select dbms_metadata.get_ddl('TABLE', 'YOUR_TABLE_NAME_HERE')
from dual;
The result is a CLOB with the complete DDL. You might need to adjust the display in SQL Developer to make the content of that value fully visible (I don't use SQL Developer, so I don't know if that is necessary and if so, what you would need to do)
Edit:
It seems SQL Developer can't display the result of this query properly unless you use the "Run Script" option. And with that you need to use a SET LONG 60000 (or some other big number) before you run it, to see the complete source code:
I have deployed an SSIS package which has a query that pulls data from oracle. The query has some variables in it and I wanted to see what variable were being inputted at run time. Is there a way maybe via sql profiler that I can capture the query that sql server is sending out to Oracle when the sql job runs?
How are these variables being 'evaluated' when the SSIS package executed? I imagine you get this from a table or generating on the 'fly'.
You have the following option :
Capture them and assign them in SSIS variable(s)
In case you are doing something complex - create a variable something like - User::SQLCommand. In this case Use expression to generate the SQL String that needs to be executed in Oracle. Use this in your OLEDB Source Editor as "Sql command from variable" to execute the statement in Oracle
Use a SQL statement to insert the variable details captured in previous step in your intended audit table
--
Please mark if this answers your question!
Is it possible to use or add parameters on a simple query without the need of creating stored procedures or function? Are Bind Variables possible without creating a stored procedures?
where are you running the code from? If your running from a language like Java / VB you would use a stored procedure or prepared statement.
If using from Sql *Plus terminal or other Sql UI
SQL> variable deptno number
SQL> exec :deptno := 10
SQL> select * from
emp where deptno = :deptno;
From a high level language like Java or VB use stored procedures, following is from the article you linked to so not sure why you are asking this?
In fact, the answer to this is actually quite simple. When you put
together an SQL statement using Java, or VB, or whatever, you usually
use an API for accessing the database; ADO in the case of VB, JDBC in
the case of Java. All of these APIs have built-in support for bind
variables, and it's just a case of using this support rather than just
concatenating a string yourself and submitting it to the database.
For example, Java has PreparedStatement, which allows the use of bind
variables, and Statement, which uses the string concatenation
approach. If you use the method that supports bind variables, the API
itself passes the bind variable value to Oracle at runtime, and you
just submit your SQL statement as normal. There's no need to
separately pass the bind variable value to Oracle, and actually no
additional work on your part. Support for bind variables isn't just
limited to Oracle - it's common to other RDBMS platforms such as
Microsoft SQL Server, so there's no excuse for not using them just
because they might be an Oracle-only feature.
Not sure why you are asking as this information is there on the site http://www.akadia.com/services/ora_bind_variables.html
Well, assuming you will perform queries using an external programming language, prepared statements will make the job.
See http://en.wikipedia.org/wiki/Prepared_statement
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.