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Message
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| mfractal |
 Posted: Mon Apr 07, 2008 2:37 pm Post subject: "Reflection" in ESQL |
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Novice
Joined: 07 Apr 2008
Posts: 14
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Good time of day to everybody!
I am having a problem ...
And the problem is that I am looking for a way to dynamically invoke ESQL procedures.
The flow is as following :
Inside ESQL i am parsing an XML file that describes a table in the DB. (I am inserting values in that table)
For every field in that DB table there is a NAME OF ESQL FUNCTION that needs to be invoked to get the value to be inserted to that field.
I'll give an example :
Consider the following XML :
| Code: |
<Table name="TTIITM001XXX">
<Fields>
<Field IN="T$CTYP" TYPE="CHAR" LENGTH="3" CALL="getProductType" />
<Field IN="T$CSIG" TYPE="CHAR" LENGTH="3" CALL="getBlockedValue" />
<Field IN="T$CUNI" TYPE="CHAR" LENGTH="3" CALL="getMetrics" />
<Field IN="T$CWAR" TYPE="CHAR" LENGTH="3" CALL="getAlCode" />
</Fields>
</Table>
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Where getProductType/getMetrics/getAlCode are the names of the functions i need to invoke to get the values for the INSERT.
Any ideas ? |
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| jefflowrey |
| Posted: Mon Apr 07, 2008 3:27 pm Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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You mean you want to evaluate a dynamic string?
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I am *not* the model of the modern major general. |
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| marcin.kasinski |
| Posted: Tue Apr 08, 2008 12:54 am Post subject: Re: "Reflection" in ESQL |
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Sentinel
Joined: 21 Dec 2004
Posts: 850
Location: Poland / Warsaw
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I think it is not possible in ESQL.
I also think it is not a good idea to send method or function name in your input XML.
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Marcin |
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| JLRowe |
| Posted: Tue Apr 08, 2008 1:20 am Post subject: |
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Yatiri
Joined: 25 May 2002
Posts: 664
Location: South East London
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| fschofer |
| Posted: Tue Apr 08, 2008 1:41 am Post subject: |
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Knight
Joined: 02 Jul 2001
Posts: 524
Location: Mainz, Germany
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| marcin.kasinski |
| Posted: Tue Apr 08, 2008 1:54 am Post subject: |
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Sentinel
Joined: 21 Dec 2004
Posts: 850
Location: Poland / Warsaw
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The EVAL statement takes a character value, interprets it as an SQL statement.
The question was about ESQL .
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Marcin |
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| jefflowrey |
| Posted: Tue Apr 08, 2008 1:58 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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No.
EVAL can run any ESQL statement....
It may be easier to do something like
CALL Procedure {myVar} ...
On the other hand that may not work at all
The real difficulty with this approach is dealing with method signatures.
_________________
I am *not* the model of the modern major general.
Last edited by jefflowrey on Tue Apr 08, 2008 1:59 am; edited 1 time in total |
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| fschofer |
| Posted: Tue Apr 08, 2008 1:58 am Post subject: |
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Knight
Joined: 02 Jul 2001
Posts: 524
Location: Mainz, Germany
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Hi,
EVAL can produce ESQL code
| Quote: |
| If it is a complete ESQL statement, the character string derived from the first stage evaluation is executed as if it were an ESQL statement |
From samples:
| Quote: |
| EVAL('SET ' || scalarVar1 || ' = 2;'); |
Greetings
Frank |
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| marcin.kasinski |
| Posted: Tue Apr 08, 2008 2:08 am Post subject: |
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Sentinel
Joined: 21 Dec 2004
Posts: 850
Location: Poland / Warsaw
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| JLRowe wrote: |
| Do it in java |
... but in JAVA I can't invoke ESQL procedures.
_________________
Marcin |
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| marcin.kasinski |
| Posted: Tue Apr 08, 2008 2:11 am Post subject: |
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Sentinel
Joined: 21 Dec 2004
Posts: 850
Location: Poland / Warsaw
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| fschofer wrote: |
Hi,
EVAL can produce ESQL code
| Quote: |
| If it is a complete ESQL statement, the character string derived from the first stage evaluation is executed as if it were an ESQL statement |
From samples:
| Quote: |
| EVAL('SET ' || scalarVar1 || ' = 2;'); |
Greetings
Frank |
Sorry, my fault 
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Marcin |
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| jefflowrey |
| Posted: Tue Apr 08, 2008 2:34 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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| marcin.kasinski wrote: |
| JLRowe wrote: |
| Do it in java |
... but in JAVA I can't invoke ESQL procedures. |
This is *very* true. The Java method for running SQL statements only lets you run a single statement. And I am pretty sure it won't let you run EVAL... 
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I am *not* the model of the modern major general. |
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| mfractal |
| Posted: Tue Apr 08, 2008 5:13 am Post subject: Re: "Reflection" in ESQL |
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Novice
Joined: 07 Apr 2008
Posts: 14
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| marcin.kasinski wrote: |
I think it is not possible in ESQL.
I also think it is not a good idea to send method or function name in your input XML. |
Well, while i generally agree with you, in this case the XML i am talking about is a service description XML, it won't be sent or recieved by anybody, it just sits there on the file system and being red when nessesary.
| jefflowrey wrote: |
EVAL can run any ESQL statement....
It may be easier to do something like
CALL Procedure {myVar} ...
On the other hand that may not work at all
The real difficulty with this approach is dealing with method signatures.
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All my functions are parameterless, so i guess that eliminates one of the issues 
Thanks to everybody, i will go and give it a try. I will report back ASAP with the results! |
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| mfractal |
| Posted: Tue Apr 08, 2008 5:25 am Post subject: Re: "Reflection" in ESQL |
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Novice
Joined: 07 Apr 2008
Posts: 14
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| mfractal wrote: |
Thanks to everybody, i will go and give it a try. I will report back ASAP with the results! |
Works like a charm!
| Code: |
| EVAL('CALL genereateBaanIDByRules();'); |
Called the procedure, not problems there! |
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