I am trying to build a stored procedure that takes in values of
#field_name
#some_rule
#from_table
#to_table
and builds up a query. Below is the code from my Stored Procedure:
CREATE PROCEDURE spBuildQuery
#field_name nvarchar(max), -- Will take field name as input
#some_rule nvarchar(max), -- Will take Some rule as a command/input from user
#from_table nvarchar(max), --to take value of table from which value to be taken
#to_table nvarchar(max), --Table where the results should be stored
#final_query nvarchar(max) OUTPUT --Output of final query
AS
IF #some_rule = 'Remove blank rows'
BEGIN
SELECT #final_query = 'SELECT * into temp1 FROM '+#from_table + ' WHERE '+ #field_name+ ' IS NOT NULL'
END
ELSE IF #some_rule = 'Rule2'
BEGIN
SELECT #final_query = 'SELECT * into temp1 FROM'+ #from_table + 'WHERE '+ #field_name+ ' IS RULE2'
END
ELSE
BEGIN
SELECT #final_query = 'Missing Value(s)'
END
--Executing the query by parsing #final_query value into #query and priting it.
DECLARE #query nvarchar(max)
EXECUTE spBuildQuery 'A Field', 'Rule2', 'Table 1', #query OUTPUT
PRINT #query
EXECUTE sp_executesql #query
My intention is to build queries based on user input like: Rules the user wants to implement what field should the rules be applied to and then display the result of that query onto a table, then that Table gets overwritten as new queries are developed. This is my intention, as another approach I was thinking is to save the built up queries into a table column and execute each query line by line using a cursor.
How can I:
a) store the built up queries into a new TEMP table?
b) execute each query using the Cursor (or any other efficient way)?
Related
I've different different tables to categorically store data and a log table where all the transactions log are recorded
e.g. 1) VoucherNO, Add, ...
2) VoucherNO, Delete, ..
After I backup the database and restore in another server for my Reporting Purpose. That time I want to ensure all the log data and transaction are available in TestDB if not then I remove log from 'AUD_USER_ACTIVITY'.
To find the transaction exist or not, I create a dynamic sql select statement and check whether record is exist or not.
Basis on #RecExist Value I do the action like if records is not available in TestDB the log will be remove, if record exist immediately break this loop and going for next procedure
But #RecExist variable is not updating in Dynamic SQL Execution. Please guide me
declare #MvDocNo varchar(50)
DECLARE #SCtr as DECIMAL(10,0)
declare #LocationCode varchar(4)
declare #UName Nvarchar(40)
declare #toe varchar(30)
declare #QryTxt as nvarchar(MAX);
Declare #RecExist as INT =0;
SET #RecExist=0
WHILE #RecExist=0
BEGIN
select top 1 #MvDocNo=DOCNO, #SCtr=SrlNo,#LocationCode =DMLTYPE,#UName=TABLENAME
FROM R_AUDDB..AUD_USER_ACTIVITY
WHERE DBNAME='TestDB' and DMLTYPE not in ('AD','D','PD') ORDER BY SRLNO DESC;
select top 1 #toe=docno from TestDB..M_TYPEOFENTRY where TBLNAME=#UName;
set #QryTxt='Select #RecExist=1 From R_TestDB..'+#UName+ ' Where '+#toe+'='''+#MvDocNo+''''
exec (#QryTxt)
IF #RecExist=0
BEGIN
DELETE R_AUDDB..AUD_USER_ACTIVITY WHERE SRLNO=#SCtr
END
END
The following code sample demonstrates how to check for a row in a table with a specific column and value using dynamic SQL. You ought to be able to change the values of the first three variables to reference a table and column in your database for testing.
Note that SQL injection is still possible: there is no validation of the table or column names.
-- Define the table to check and the target column name and value.
declare #TableName as SysName = 'Things';
declare #ColumnName as SysName = 'ThingName';
declare #TestValue as NVarChar(32) = 'Beth';
-- Create a SQL statement to check for a row in the target table with the specified column name and value.
declare #SQL as NVarChar(1024);
declare #Result as Bit;
-- Note that only object names are substituted into the statement at this point and QuoteName() is used to reduce problems.
set #SQL = N'select #iResult = case when exists ( select 42 from dbo.' + QuoteName( #TableName ) +
N' where ' + QuoteName( #ColumnName ) + N' = #iTestValue ) then 1 else 0 end;'
select #SQL as SQL;
-- Execute the SQL statement.
-- Note that parameters are used for all values, i.e. the target value and return value.
execute sp_executesql #stmt = #SQL,
#params = N'#iTestValue NVarChar(32), #iResult Bit output',
#iTestValue = #TestValue, #iResult = #Result output
-- Display the result.
select #Result as Result;
I am very new to DB2 even though have experience in Oracle. I am not able to resolve this issue.I have a requirement where I need to find missing child records in the parent table .The parent table , child table and the join_key are all passed as input parameter.
I have tried this in a procedure was able to achieve this, but the admin wants it in a function so that they can just use it in a select statment and get the result in a table format. Since the parent table , child table and the join_key are comming as input parement, I am not able to run them as dynamic sql.
create or replace function missing_child_rec(PARENT_TBL VARCHAR(255),JOIN_KEY VARCHAR(255),CHILD_TBL VARCHAR(255))
RETURNS TABLE(Key VARCHAR(255))
LANGUAGE SQL
BEGIN
DECLARE V_SQL VARCHAR(500);
DECLARE C_SQL CURSOR WITH RETURN FOR S_SQL;
SET V_PARENT_TAB = PARENT_TBL;
SET V_KEY = JOIN_KEY;
SET V_CHILD_TAB = CHILD_TBL;
SET V_SQL = 'SELECT DISTINCT '|| JOIN_KEY || ' FROM ' || V_CHILD_TAB || ' A WHERE NOT EXISTS
(SELECT ' ||V_KEY || ' FROM ' || V_PARENT_TAB || ' B WHERE A.'||JOIN_KEY || '= B.'||JOIN_KEY ||' )' ;
PREPARE S_SQL FROM V_SQL;
OPEN C_SQL;
CLOSE C_SQL;
RETURN
END
When I try to compile it , it says prepare is invalid , I have tried even execute immediate but that also gave error.Can you please help me with how to use dynamic sql in UDF or an alternative logic for this problem
There is more than one way to solve this, here's one way.
If you already have a working stored-procedure that returns the correct result-set then you can call that stored-procedure from a pipelined table function. The idea is that a pipelined table function can consume the result-set and pipe it to the caller.
This will work on Db2-LUW v10.1 or higher, as long as the database is not partitioned over multiple nodes.
It may work on Db2-for-i v7.1 or higher.
It will not work with Db2 for Z/os at current versions.
Suppose your stored procedure is sp_missing_child_rec and it takes the same input parameters as the function you show in your question, and suppose the data type of the join column is varchar(100).
The pipelined wrapper table function would look something like this:
--#SET TERMINATOR #
create or replace function missing_child_rec(PARENT_TBL VARCHAR(255),JOIN_KEY VARCHAR(255),CHILD_TBL VARCHAR(255))
returns table ( join_column_value varchar(100))
begin
declare v_rs result_set_locator varying;
declare v_row varchar(100); -- to match the join_column_datatype, adjust as necessary
declare sqlstate char(5) default '00000';
CALL sp_missing_child_rec( parent_tbl, join_key, child_tbl);
associate result set locator (v_rs) with procedure sp_missing_child_rec ;
allocate v_rscur cursor for result set v_rs;
fetch from v_rscur into v_row;
while ( sqlstate = '00000') do
pipe(v_row);
fetch from v_rscur into v_row;
end while;
return;
end#
select * from table(missing_child_rec( 'parent_table' , 'join_column', 'child_table'))
#
I have a DB2 Stored Procedure that runs for nearly 4 minutes and fetches 6000 pages of data.
Please may I know if there are any possible query-performance tuning methods in DB2 so that the procedure could be made to execute faster.
The basic structure of the stored procedure created is
CREATE PROCEDURE SAMPLE_PROC(ID INT)
RESULT SETS 1
P1: BEGIN
DECLARE GLOBAL TEMPORARY TABLE SESSION.TEMP1
(
COLUMN_NAMES
)ON COMMIT DROP TABLE;
BEGIN
DECLARE V_PARAM_1 VARCHAR(8000);
DECLARE V_PARAM_2 VARCHAR(8000);
DECLARE CURSOR1 CURSOR WITH RETURN FOR
SELECT
COLUMN_NAMES
FROM SESSION.TEMP1
GROUP BY
COLUMN_NAMES
WITH UR;
SELECT
RTRIM(IFNULL(PARAM_1, '')) PARAM_1,
RTRIM(IFNULL(PARAM_2, '')) PARAM_2
INTO
V_PARAM_1,
V_PARAM_2
FROM
PARAM_TABLE
WHERE
PARAM_ID = ID;
INSERT INTO SESSION.TEMP1(COLUMN_NAMES)
SELECT COLUMNS FROM (....) WHERE(...);
OPEN CURSOR1;
END;
END P1#
The procedure consists of a select which returns values from the PARAM_TABLE to be passed as parameters to the original query. Multiple comma separated values are passed from the table to the query.
Thanks
In continuation to a previous case (a solution by #Erwin Brandstetter), in which a dynamic SELECT query that uses a 'prepare' statement was created and then was executed by calling it, as below:
--the function for making the prepare statement:
CREATE OR REPLACE FUNCTION f_prep_query (_tbl regclass, _prefix text)
RETURNS void AS
$func$
DECLARE
_prep_qry text := (
SELECT 'PREPARE stmt_dyn AS SELECT '
|| string_agg(quote_ident(attname), ',' ORDER BY attname)
|| ' FROM ' || _tbl
FROM pg_attribute
WHERE attrelid = _tbl
AND attname LIKE _prefix || '%'
AND attnum > 0
AND NOT attisdropped
);
BEGIN
EXECUTE _prep_qry;
EXCEPTION WHEN duplicate_prepared_statement THEN
DEALLOCATE stmt_dyn;
EXECUTE _prep_qry;
END
$func$ LANGUAGE plpgsql;
--the calling:
BEGIN; -- optional
SELECT f_prep_query('dkj_p_k27ac'::regclass, 'enri'::text);
EXECUTE stmt_dyn;
I would like to ask the following:
The desired output that we get from the indicated procedure is outputted into the DataOutput.
I would like to find a way to store the data into a new table in the db.
Generally, if you just want to write to a table, don't use a prepared SELECT statement (or a cursor). That's very inefficient for the purpose.
Write to the table directly like explained in the previous answer:
Saving the output of a dynamic query that uses refcursor into a table
The complete INSERT could be the prepared statement. But not CREATE TABLE AS. Per documentation:
Any SELECT, INSERT, UPDATE, DELETE, or VALUES statement.
I have a number of stored procedures structured similarly to this:
DECLARE #sql NVARCHAR(MAX)
DECLARE #mdx NVARCHAR(MAX)
CREATE table #result
(
[col1] NVARCHAR(50),
[col2] INT,
[col3] INT
)
SET #mdx = '{some dynamic MDX}'
SET #sql = 'SELECT a.* FROM OpenQuery(LinkedAnalysisServer, ''' + #mdx + ''') AS a'
INSERT INTO #result
EXEC sp_executesql #sql
SELECT * FROM #result
This works quite well when results exist in the cube. However, when the OpenQuery results are empty, the INSERT fails with this error:
Column name or number of supplied
values does not match table
definition.
My question is, what is the best way to handle this scenario? I'm using the results in a static report file (.rdlc), so the explicit typing of the temp table is (I'm pretty sure) required.
Use TRY/CATCH in your stored procedure, you'll notice there is a specific error number for your problem, so check the error number and if it is that, return an empty result set. As you already have the table defined that'll be easier.
PseudoCode looks something like this:
SET #mdx = '{some dynamic MDX}'
SET #sql = 'SELECT a.* FROM OpenQuery(LinkedAnalysisServer, ''' + #mdx + ''') AS a'
BEGIN TRY
INSERT INTO #result
EXEC sp_executesql #sql
END TRY
BEGIN CATCH
IF ERROR_NUMBER <> 'The error number you are seeing'
BEGIN
RAISERROR('Something happened that was not an empty result set')
END
END CATCH
SELECT * FROM #result
You'll want to check for that particular error, so that you don't just return empty result sets if your SSAS server crashes for example.
There is another solution to this issue, similar to the accepted answer, which involves using an IF statement instead of TRY...CATCH.
http://www.triballabs.net/2011/11/overcoming-openquery-mdx-challenges/
IF (SELECT COUNT(*)
FROM OPENQUERY("SSAS1",
'SELECT [Measures].[Target Places] ON COLUMNS
FROM [ebs4BI_FactEnrolment]
WHERE [DimFundingYear].[Funding Year].&[17]')) > 0
EXEC sp_executesql N'SELECT CONVERT(varchar(20),
"[DimPAPSCourse].[Prog Area].[Prog Area].[MEMBER_CAPTION]")
as ProgArea,
convert(float, "[Measures].[Target Places]") as Target
FROM OPENQUERY("SSAS1",
''SELECT [Measures].[Target Places] ON COLUMNS,
[DimPAPSCourse].[Prog Area].[Prog Area] ON ROWS
FROM [ebs4BI_FactEnrolment]
WHERE [DimFundingYear].[Funding Year].&[17]'')'
ELSE
SELECT '' as ProgArea, 0 as Target
WHERE 1=0