How can I write a SQL statement which checks if a table exists?

How can I write a SQL statement which tells me whether a table exists?

execute an sql query: select * from <tablename>
catch the exception n check whether the erroe code
matches the one that occurs for table doesn't exist
that's itHow is your answer any different from the one given in the first reply?
It isn't.
As WorkForFood says DatabaseMetaData has a bunch of methods for getting information about tables but this is more useful when you don't know the names of any of the tables.. it sounds like you do so I would concur SELECT from table is probably the quickest way to go. If it helps the Xopen error should be either S1000 or 42S01 (I think) but I would try and see if there is a specific vendor code for table not found/not exists error and check for that.

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Q: how can i write PL/SQL block to check prerequisite?

Hello...
I designed an application using sql*plus statment for creating database and developer for creating forms, for on-line registration system for universties,
so I need to teach me how can I write pl/sql block to check the prerequisite, taken courses, and complete hours for the students who wants register the courses via Internet.
thanks alot in advance
kindly send the answers a.s.a.p

please repost this in the SQL & PL/SQL forum
thanks - OTN

How can i use one SQL statement to solve problem?

How can i use one SQL statement to solve the question below?
For a Table named A, there is a column named F(char type).
Now select all the records where F like '%00' and update their F value to '%01'
Just one SQL statement.Do not use PL/SQL block.
How to do that?
Thanks.

What is the data volume for this table?
Do you expect lots of rows to have '%00' as their value?
Following two statements come to mind. Other experts would be able to provide better alternatives:
If you have index on SUBSTR(f, 2):
UPDATE A
SET    f = SUBSTR(f,
                  1,
                  length(f) - 2) || '01'
WHERE substr(f,
              -2) = '00';If most of the rows have pattern '%00':
UPDATE A
SET    f = SUBSTR(f,
                  1,
                  length(f) - 2) ||
           DECODE(SUBSTR(f,
                         -2),
                  '00',
                  '01',
                  SUBSTR(f,
                         -2));

Can I write merge SQL statement having count(*)?

Hi this is a followup question of my previous post. I tried to use a merge SQL statement to solve my problem but now I bump into another problem.
Now I have a table where the field I need to update is a partial PK
when using a merge SQL statement, I have to put a where clause that check if count(*) = 1 because of the PK constraint
Where can I put the count(*) = 1 clause?
Here are the details:
I have two tables TA and TB, where TA contains the fields ID, FULLNAME, TYPE and TB contains the fields ID, FIRSTNAME
I want to update the firstnames in TB to be the firstnames from TA where TB.ID = TA.ID and TA.TYPE = 'ABC'
{ID, FIRSTNAME} are PKs but for the same ID, there can be more than 1 firstname.
e.g.
TA
ID | FULLNAME | TYPE
1 Caroline T ABC
2 Mary C DEF
3 Peter J ABC
TB
ID | FIRSTNAME
1 Caroline
1 Carol
1 C,
3 Peter
I need to update TB with the new firstnames from TA where type is 'ABC' but only for those fields that have count(TB.ID) = 1
when I try to run this SQL statement
merge into TB B using TA A
on (A.ID = B.ID and A.TYPE = 'ABC')
when matched then update set B.FIRSTNAME = substr(A.FULLNAME, 1, instr(A.FULLNAME, ',') - 1)
I got this error SQL Error: ORA-00001: unique constraint (TEST.PK_TB) violated
which I believe is because I updated those fields say ID = 1, all with 'Caroline'
that means I will have to add a clause having count(TB.ID) = 1
How would you do it?
Server is Oracle 11g
Thank you!

Hi,
One way is to join ta and tb in the USING clause, and eliminate the duplicates there.
MERGE INTO     tb     dst
USING   (
         SELECT    ta.id
         ,           REGEXP_SUBSTR ( MIN (ta.fullname)
                                , '^[^,]*'
                        )     AS firstname
         FROM      ta
         JOIN      tb ON ta.id     = tb.id
         WHERE     ta.type      = 'ABC'
         GROUP BY ta.id
         HAVING    COUNT (*)     = 1
     )                   src
ON     (scr.id      = dst.id)
WHEN MATCHED THEN UPDATE
SET     dst.firstname     = src.firstname
;If you'd care to post CREATE TABLE and INSERT statements for your sample data, then I could test this.
I used REGEXP_SUBST instead of SUBSTR and INSTR to find the firstname, because I find it a little cleaner, and becuase it returns something even when there is no ',' in fullname, which I'm guessing is what you really want. (None of the fullnames in your sample data have ','s.) You could use SUBSTR and INSTR instead.

How to tune the following sql statements which has two unions in oracle 10g

It takes a long time to run the following sql statement in 10g. Each select brings back about 4 million rows and there will be about 12 million rows. When I run each select statements seprately in sqlplus I can see the data immedaitely but when I run it as whole with two unions in the select it just takes very very long time? I want to know how to make this run faster? Can we add hints? or is it because of any table space? Any help is appreciated.
select
D.EMPLID
,D.COMPANY
,'CY'
,D.CALENDAR_YEAR
,D.QTRCD
,D.ERNCD
,D.MONTHCD
,D.MONTHCD
,D.GRS_MTD
,D.GRS_QTD
,D.GRS_YTD
,D.HRS_MTD
,D.HRS_QTD
,D.HRS_YTD
from PS_EARNINGS_BAL D
where D.SPCL_BALANCE = 'N'
union
select
D.EMPLID
,D.COMPANY
,'FY'
,(case when D.MONTHCD > '06' then D.CALENDAR_YEAR + 1 else D.CALENDAR_YEAR end)
,ltrim(to_char(to_number(D.QTRCD) + decode(sign(3-to_number(D.QTRCD)),1,2,-2),'9'))
,D.ERNCD
,ltrim(to_char(to_number(D.MONTHCD) + decode(sign(7-to_number(D.MONTHCD)),1,6,-6),'09'))
,D.MONTHCD
,D.GRS_MTD
,D.GRS_QTD
,(select sum(F.GRS_MTD) from PS_EARNINGS_BAL F where
F.EMPLID = D.EMPLID and
F.COMPANY = D.COMPANY and
F.ERNCD = D.ERNCD and
F.SPCL_BALANCE = D.SPCL_BALANCE and
(case when F.MONTHCD < '07' then F.CALENDAR_YEAR -1 else F.CALENDAR_YEAR end)
= (case when D.MONTHCD < '07' then D.CALENDAR_YEAR -1 else D.CALENDAR_YEAR end)
and to_number(F.MONTHCD) + decode(sign(7-to_number(F.MONTHCD)),1,6,-6)
<= to_number(D.MONTHCD) + decode(sign(7-to_number(D.MONTHCD)),1,6,-6))
,D.HRS_MTD
,D.HRS_QTD
,(select sum(F.HRS_MTD) from PS_EARNINGS_BAL F where
F.EMPLID = D.EMPLID and
F.COMPANY = D.COMPANY and
F.ERNCD = D.ERNCD and
F.SPCL_BALANCE = D.SPCL_BALANCE and
(case when F.MONTHCD < '07' then F.CALENDAR_YEAR -1 else F.CALENDAR_YEAR end)
= (case when D.MONTHCD < '07' then D.CALENDAR_YEAR -1 else D.CALENDAR_YEAR end)
and to_number(F.MONTHCD) + decode(sign(7-to_number(F.MONTHCD)),1,6,-6)
<= to_number(D.MONTHCD) + decode(sign(7-to_number(D.MONTHCD)),1,6,-6))
from PS_EARNINGS_BAL D
where D.SPCL_BALANCE = 'N'
union
select
D.EMPLID
,D.COMPANY
,'FF'
,(case when D.MONTHCD > '09' then D.CALENDAR_YEAR + 1 else D.CALENDAR_YEAR end)
,ltrim(to_char(to_number(D.QTRCD)+decode(sign(4-to_number(D.QTRCD)),1,1,-3),'9'))
,D.ERNCD
,ltrim(to_char(to_number(D.MONTHCD)+decode(sign(10-to_number(D.MONTHCD)),1,3,-9),'09'))
,D.MONTHCD
,D.GRS_MTD
,D.GRS_QTD
,(select sum(F.GRS_MTD) from PS_EARNINGS_BAL F where
F.EMPLID = D.EMPLID and
F.COMPANY = D.COMPANY and
F.ERNCD = D.ERNCD and
F.SPCL_BALANCE = D.SPCL_BALANCE and
(case when F.MONTHCD < '10' then F.CALENDAR_YEAR -1 else F.CALENDAR_YEAR end)
= (case when D.MONTHCD < '10' then D.CALENDAR_YEAR -1 else D.CALENDAR_YEAR end)
and to_number(F.MONTHCD)+decode(sign(4-to_number(F.MONTHCD)),1,9,-3)
<= to_number(D.MONTHCD)+decode(sign(4-to_number(D.MONTHCD)),1,9,-3))
,D.HRS_MTD
,D.HRS_QTD
,(select sum(F.HRS_MTD) from PS_EARNINGS_BAL F where
F.EMPLID = D.EMPLID and
F.COMPANY = D.COMPANY and
F.ERNCD = D.ERNCD and
F.SPCL_BALANCE = D.SPCL_BALANCE and
(case when F.MONTHCD < '10' then F.CALENDAR_YEAR -1 else F.CALENDAR_YEAR end)
= (case when D.MONTHCD < '10' then D.CALENDAR_YEAR -1 else D.CALENDAR_YEAR end)
and to_number(F.MONTHCD)+decode(sign(4-to_number(F.MONTHCD)),1,9,-3)
<= to_number(D.MONTHCD)+decode(sign(4-to_number(D.MONTHCD)),1,9,-3))
from PS_EARNINGS_BAL D
where D.SPCL_BALANCE = 'N'
Edited by: user5846372 on Mar 11, 2009 8:55 AM

Hi,
What i observed is that your table name and where clause is same in all the thress SELECTs whereas columns having some manipulations that is not going to be unique. I guess you can easily replace UNION with UNION ALL.
from PS_EARNINGS_BAL D
where D.SPCL_BALANCE = 'N'Note: I am not aware of your data and business requirement. Please test the result before removing. It is just a suggetion
Cheers,
Avinash

How can I execute Dynamic SQL statement in Forms?

Hi All,
I have to execute dynamic SQL statement from Forms
Below statement I have to execute
"EXECUTE IMMEDIATE v_stmt INTO v_return;".
Googled for the same got results saying, Better use Database function or procedures to execute these Dynamic Statements but We want to execute in forms only.
Can any one help me..
Thanks,
Madhu

So in short you are trading code obfuscation for maintainability and the ability to share code between tools? If from somewhere else you need a procedure already implemented in database PL/SQL (and now ported to forms) this would mean you'd need to implement it in every other tool. In times where you might want to integrate your forms with $other_technology and putting stuff on the database is the first step to share functionality you just go the opposite way? And all that because someone is afraid that somebody might steal your source code? I am sorry to be blunt, but this is just plain stupid.
Leaving aside that some things like Analytic Functions, Bulk processing or execute immediate are not even available in forms your software consists of how many LOC? How long does it take to bring a new developer up to speed with your source code? Imagine how long that would take for a developer who doesn't have coleagues who know their way around.
And just so you know: I work for a ISV selling a closed-source product as well. We have 200+ customers all over the planet. We are well aware that wrapped packages can be reverse engineered. The premise is: stored procedures can be reused in every tool we have, if it makes sense to put stuff on the database by all means do it. If someone would want to reverse engineer our software I'd wish him good luck as some parts are implemented in such a hilarious complicated way I have troubles understanding them (and quite frankly I refuse to understand certain parts, but that's another story). I do work for almost 10 years for that ISV.
In any case the possible solutions have already been mentioned: you have exec_sql, create_group_from_query and forms_ddl to execute dynamic SQL in forms whereas forms_ddl is a one way street and most certainly not the thing you need or want. Take a look at the documentation for the other 2 things.
cheers

How can I get the MDX-statement which is generated in a query?

Can I somehow get the MDX statement, which is generated when I create a Query via BeX Query Designer? I am using JCo to connect to BW (3.0b) and to execute MDX statements from a standalone JAVA-application. It would be very helpful to have the statements, so that I don't have to create them by myself.
If this it not possible...is there any reference regarding the MDX statements, I could use?

Hi Markus,
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https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/com.sap.km.cm.docs/library/uuid/a06a51f3-0201-0010-8591-b742cfafd267
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How can we tell if SQL*Loader is working on a TABLE?

We have a process that requires comparing batches with LDAP information. Instead of using an LDAP lookup tool, we get a nightly directory file, and import the two COLUMNs we want via SQL*Loader (REPLACE) into an IOT. Out of three cases, two just check the first COLUMN, and the third needs the second COLUMN as well.
We did not think of using External TABLEs, because we cannot store files on the DB server itself.
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I can think of three solutions:
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Just out of curiosity, are you aware that Oracle supplies a DBMS_LDAP package for pulling information from LDAP sources? It would obviously be relatively easy to have a single transaction that deletes the existing data, loads the new data via DBMS_LDAP, and commits, which would get around the problem you're having with SQL*Loader truncating the table.
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How can i write the following statements in Java ???

Hi Everyone,
I'm studying UML and according to my textbook, it says if 2 classes have the following relationship then it can be said that there's an association relationship between those 2 classesl.
Class A and B are associated if :
- an object of class A sends a message to an object of class B
- an object of class A creates an object of class B
- an object of class A has an attribute whose value are objects of class B or collections of objects of class B
- an object of class A receives a message with an object of class B as an argument.
However, I dunno how to write those stuff into Java codes. Can someone please kindly write Java codes for those sentences ?? Thanks everyone in advance.

Sorry guys. I know I shouldn't have asked in the first place without giving it a try first. Yeah, I been doing
Java without understanding the concept of real OOP and its terms.
- an object of class A sends a message to an object of class B // ?????
- an object of class A creates an object of class B // A obj=new A();
- an object of class A has an attribute whose value are objects of class B or collections of objects of class B // A varB;
- an object of class A receives a message with an object of class B as an argument. // ?????
I get confused with the very first line and the last line . I dunno what it means by sending a message but according to what JoachimSauer mentioned
it's "calling a method" but does that mean even I called an object of the same class within , can i still refers it as sending a message ?? Like what if
i call a static method of the calling object because I dun think i create an object when I call a static method ?
Let's say
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     public void displayOne()
          System.out.println("Just an exampleOne");
class ExampleTwo
     public ExampleTwo()
          ExampleTwo.display(); // here no object creation occurs , just ExampleTwo class sends a message to itself so there's no association i assume .
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          System.out.println("Just an exampleTwo");
public class Main
     public static void main(String args[])
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How can I write this SQL?

the statement have the question:
     stxh-tdname length 70
     itab-vbeln       length 10
select tdobject into table it_stxh
    from stxh
    for all entries in itab
    where ( tdid = 'Z006' and tdspras = 'E'      and tdname+0(10) = itab-vbeln and tdobject = 'VBBK' ).
tdname+0(10) = itab-vbeln ???

When you define the first Internal Table ITAB, define vbeln as the same type of stxh-tdname.
Eg.
data: begin of itab occurs 0,
          vbeln like STXH-TDNAME,
          erdat like vbak-erdat,
          end of itab.
START-OF-SELECTION.
Select VBELN
          ERDAT
from vbak
into CORRSPONDING FIELDS of table itab.
Then you can directly use this ITAB in the next query
select tdobject into table it_stxh
from stxh
for all entries in itab
where ( tdid = 'Z006' and tdspras = 'E' and tdname = itab-vbeln
and tdobject = 'VBBK' ).
Pls reward it if it is useful.

How can i write a Pl/sql Programme for a calender

hi all,
How can i write Pl/sql programme (may be function) for a calendar ,like after the programme is created if call the function at the prompt and give the year 2099 so on, it should display the result with all the 12 months (months and days.)
Please email the answer to
[email protected]
or send the link for the answers.
Thx

Well, you can start off by reviewing the SYSDATE command and the TO_DATE and TO_CHAR functions. Also, review addmonths etc.
http://www.unix.org.ua/orelly/oracle/prog2/ch14_01.htm
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I have some embedded SQL statements to create tables and indexes
in a database. These tables may or may not already be there. I
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that does not exist.
Can someone send me the proper SQL command to check if a table
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TIA
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null

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would like to be able to drop the table(s) first, then create
them. Unfortunately, an error is generated if I drop a table
that does not exist.
Can someone send me the proper SQL command to check if a table
exists before dropping it in Oracle?
TIA
Eric
null

How to run a SQL statement which is stored inside an SQL Table

Hello,
If anyone please help me with the following problem I would be forever grateful
I have an SQL statement which is stored inside a certain SQL table, I want to use that SQL statement inside my PL/SQL procedure.
Was thinking of a simple solution of obtaining the SQL statement into an array and then execute it, yet how could I do so exactly with PL/SQL? I've only started playing around with PL/SQL in the last few days.
Thanks in advance!
This is how it looks like more or less:
Displaying result for:
SELECT TRIM(OBJ_VALU_TXT)
FROM OBJ_VALU_DOC
WHERE OBJECT_TYPE = 'FLD'
AND OBJECT_CODE = 15443
AND OBJ_VALU_CD = 'ACR'
ORDER BYDOC_SEQ_NO
00001
SELECT
VALUE(MAX(RECEIPT_NO) + 1, :OUT-COMP-FACTOR)
FROM RECEIPT
WHERE (RECEIPT_NO BETWEEN
:OUT-COMP-FACTOR AND :OUT-TO-NUMBER) OR
(RECEIPT_NO > :OUT-COMP-FACTOR AND
:OUT-TO-NUMBER = 0)

Here's a demo of your requirement.
create table t ( col1 varchar2(200));
table created
insert into t values('select * from dual');
1 row inserted
declare
v_col varchar2(200);
v_val varchar2(200);
begin
select col1 into v_col from t;
execute immediate v_col into v_val;
dbms_output.put_line(v_val);
end;
X
Using into clause, you can use as many variables as required. But the basic approach reamins the same.
But storing SQL in DB is not an efficient design.
Ishan

How to write the sql statement of my finder function in cmp?

hi,
I create a cmp ejb from table INFOCOLUMN,and I create a my finder function ,which sql statement is :
select * from INFOCOLUMN WHERE employee_id=id
employee_id is a column of the table,and id is the finder function parameter.
The error is : invalid column name
So,how to write the sql statement.
Thanks .

Mole-
Bind variables are of the form $1, $2, etc., so your query stmt should look like:
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How can I write cursor which tell me no record exists

Hi Experts,
I want to know how can I write a cursor which told me no record exists before opening and running the loop.
So I want that if no record exist then I dont want to run loop and open the cursor.
Example: cursor c1 is select empno from scott.emp where empno=10
In procedure body, I want to check if there is no record against my cusor then I don't like to open it.
Thanks

Rizwan Ali Wahla wrote:
I want to know how can I write a cursor which told me no record exists before opening and running the loop.
So I want that if no record exist then I dont want to run loop and open the cursor.Not possible.
Example: cursor c1 is select empno from scott.emp where empno=10Single row? No need for an explicit cursor. No need for a loop. It can be done using an implicit cursor. E.g.
SQL> create or replace function GetEmployee( empID number ) return EMP%RowType is
2          empRow EMP%RowType;
3 begin
4          select
5                  e.* into empRow
6          from    emp e
7          where   e.empno = empID;
8          return( empRow );
9 exception when NO_DATA_FOUND then
10          return( null );
11 end;
12 /
Function created.
SQL>
SQL> declare
2
3          procedure ProcessEmp( empID number ) is
4                  empRow EMP%RowType;
5          begin
6                  empRow := GetEmployee( empID );
7
8                  if empRow.empno is null then
9                          dbms_output.put_line( 'Employee '||empID||' does not exist.' );
10                  else
11                          dbms_output.put_line(
12                                  'Employee '||empID||' is '||empRow.ename ||
13                                  ' and employed as '||empRow.job
14                          );
15                  end if;
16          end;
17
18 begin
19          ProcessEmp( 7900 );
20          ProcessEmp( 7901 );
21 end;
22 /
Employee 7900 is JAMES and employed as CLERK
Employee 7901 does not exist.
PL/SQL procedure successfully completed.
SQL> All SQLs are cursors. Every single SQL passed to Oracle for parsing and execution is a cursor. So it does not make sense to use one SQL cursor for testing the existence of a specific row, and then another to return the row.
That kind of logic is PL/SQL logic and a single SQL cursor need to be used.
PS. Make sure that the SQL projection only includes the columns needed in PL/SQL. If the SQL is a pure exist row? check, then do not return any column and use a literal value as the projected column.
Edited by: Billy Verreynne on Feb 16, 2012 5:55 AM

How can I write a SQL statement which checks if a table exists?

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