WMB Best Practices and ESQL Development Guidelines

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Integration Standards

WMB Best Practices &

ESQL Development Guidelines

v1.0

April 7, 2016

Printed on 4/7/2016


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WMB Best Practices & ESQL DevelopmentGuidelines

Document History

Revision History

VersionNo

!evisionDate

Summary o" #$an%es !evision By

0.1 22-May-07 First Draft version Santanu Mitra

1.0 01-De-07 First !eleased version Santanu Mitra

Document Distribution List

Name itle

Dou"ent# $126%07$7.do Printed on 4/7/2016 Date# %&7&2016

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a'le o" #ontents

1 Introdution................................................................................................................(

2 'urpose.....................................................................................................................(

$ Assu"ptions..............................................................................................................(

% )e*Sp+ere M est 'raties..................................................................................6

%.1 nderstand t+e Interfae usiness !euire"ent.............................................................6

%.2 Interfae Design /ayout....................................................................................................6

%.$ o""on +arateristis of Interfaes..............................................................................6

%.% o""on rror&eption 3andling..................................................................................6

%.( o""on ontrol 3andling...............................................................................................6

%.6 o""on !outines and Su*-Flo4s...................................................................................7

%.7 /oation of Integration /ogi............................................................................................7

%.5 nderstand t+e Input and utput Messages....................................................................7

%. Deter"ine +o4 "any Message Flo4s are needed...........................................................7

%.10 o"plete t+e proessing 4it+ as fe4 nodes as possi*le..........................................5

%.11 Message !outing 4it+in a flo4..................................................................................5

%.12 Su*Flo4s...................................................................................................................5

%.1$ 8ransationality and 'ersistene...............................................................................5

%.1% se of A!DI9A/I8:...............................................................................................

%.1( S;/ !F!9


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(.5.2 IF State"ent............................................................................................................1%

(.5.$ AS State"ent.....................................................................................................1(

(.5.% S/8 State"ent.................................................................................................1(

(.5.( I9S!8 State"ent..................................................................................................1(

(.5.6 pdate State"ent...................................................................................................16

(.5.7 D/8 State"ent.................................................................................................16

(. Delarations....................................................................................................................16

6 Appendi 1. I"portant Strutures............................................................................17

6.1 M;MD @ Message Desriptor........................................................................................17

6.2 M;!F32 @ !ules and For"atting 3eader.....................................................................15

6.$ 'roperties @ Message Flo4............................................................................................15

7 Appendi 2. De*ug 8raing......................................................................................20

5 A Sa"ple S;/.......................................................................................................21


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( )ntroduction

8+is dou"ent presents so"e findings and reo""endations onerning t+e use of )e*Sp+ereMessage ro>er )MB. 8+ese findings 4ere developed fro" previous eperienes of variousintegration proCets. It overs t+e aspets of )M develop"ent eno"passing Message Setguidelines, Message Flo4 guidelines and Deploy"ent guidelines.

* Purpose

8+is dou"ent an serve as a *aseline for Integration 'roCets using )M 4it+ a little or no"odifiations as appropriate.

+ ,ssumptions• 'rior 4or>ing level of >no4ledge on )M for t+e readers of t+is dou"ent.


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- We'Sp$ere MB Best Practices

4.1Understand the Interface Business Requirement

8+e first >ey to suessful 8e+nial Design and Interfae Develop"ent is a fir" >no4ledge of t+e intended *usiness logi and struture. 8+e soure to t+e usiness !euire"ent is to auirea fir" and defined Funtional Speifiation. 8o so"e degree, t+e Funtional Speifiation "ayundergo a fe4 "inor a"end"ents 4+ile t+e tas> of 8e+nial Speifiation is under4ay.3o4ever, it is epeted t+at t+e Funtional Speifiation +as defined all t+e "essages,o"ponents and proesses t+at are reuired for t+e interfae *efore t+e o""ene"ent of 8e+nial Design.

8+ere "ay *e and usually isB "ultiple o"ponents to ea+ interfae, and in )M ter"s, t+at*oils do4n to Adapters and Message Flo4s. 8+e Funtional Speifiation is used to define 4+eret+e usiness !euire"ents are "et in ter"s of various o"ponents. It is reuired to onsider t+e

various options availa*le and reate a design t+at is *ased on 4or>a*le funtionality of )M,and to +opefully end up 4it+ a reasona*le level of "aintaina*ility and perfor"ane as 4ell.

4.2Interface Design Layout

8+e )M interfaes to *e i"ple"ented s+ould +ave ertain o""on +arateristis so t+at re-use of o"ponents is opti"ied. 8+e design of t+e "essage flo4s s+ould ad+ere to one or "oreof t+e pattern te"plates laid out for t+e proCet. 3o4ever, t+ere an *e ases 4+ere t+ereuire"ent of t+e interfae is su+ t+at t+ere is no pattern te"plate "at+ing to lay out t+edesign of t+at interfae. 8+is ase is to *e treated as a speial ase and a ne4 pattern te"platefor t+is ase s+ould *e first designed *efore "oving for t+e te+nial design of t+e interfae.3o4ever, ourrene of su+ event is least epeted and if ours, definition of a ne4 patternte"plate s+ould *e t+e last +osen option.

4.3Common Characteristics of Interfaces

a+ )M Interfae designed for t+e proCet s+ould +ave ertain +arateristis 4+i+ areassu"ed to *e o""on aross all i"ple"ented interfaes. 8+ese o""on +arateristisgenerally refer to so"e o""on routines and flo4s or su*-flo4s 4+i+ are reo""ended to *eused glo*ally aross all interfaes in t+at proCet.

4.4Common Error/Exception Handling

a+ )M interfae s+all +ave a "e+anis" to +andle errors&eeptions. 8+ese

errors&eeptions refer to *ot+ Syste"s generated ones as 4ell as ser ?enerated ones. It isreo""ended to +ave a o""on rror 3andling 'roedure&Module to +andle allerrors&eeptions t+at arise during eeution of an interfae. 8+is 'roedure&Module s+all *eetensively re-used *y all interfaes of t+e proCet.


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4.5Common Control Handling

8+e flo4 of ea+ "essage t+roug+ a )M interfae s+ould *e Eontrol 3andled for audit andlogging purpose. For t+is reason, t+ere is a reuire"ent to +ave a Eontrol Me+anis" in ea+and every "essage flo4. It is reo""ended to +ave a Eo""on ontrol 3andling

routine&o"ponent t+at an *e re-used etensively *y all interfaes of t+e proCet.

4.6Common Routines and Sub-Flows

Many "essage flo4s reuire to perfor" ertain funtions li>e re-for"atting a date, getting urrentdate, getting a uniue identifier, et 4+i+ an *e laid do4n as o""on routines for re-use *y t+einterfaes. Also t+ere "ay *e ertain proesses li>e adding an !F32 +eader to a "essage, et4+i+ an also *e laid do4n as o""on su*-flo4s for re-use *y interfaes.

It is reo""ended to +ave a set of o""on routines and su*-flo4s for t+e proCet t+at an *eetensively re-used *y t+e interfaes. 8+e ontents of t+is set annot *e defined e+austively atany point of ti"e. 8+is set s+all ontinually *e gaining "e"*ers fro" ti"e to ti"e in order to "eetreuire"ents.

4.7Location of Integration Logic

An interfae is o"prised of Adapters and Message Flo4s. 8+e integration logi is t+ereforeontained 4+olly 4it+in t+e adapters and "essage flo4s.

8+e interfae designer +as t+e option of *uilding any reuired integration logi in t+e adapters or "essage flo4s. It is reo""ended t+at as "u+ *usiness logi as possi*le 4ill *e perfor"ed in"essage flo4s rat+er t+an in t+e adapters. In essene logi is only to *e loated in adapters if t+at is t+e only option for t+e interfae.

In ot+er 4ords, adapters 4ill "e "ade as si"ple as possi*le. 8+e ore of t+e *usiness logis+ould *e >ept in )M.

8+e *enefits of t+is approa+ are#

• 8+e interfae solutions are pattern *ased, 4it+ t+e patterns represented *y )M "essage

flo4s. eing pattern *ased, en+anes reusa*ility.

• Saling and resiliene is si"plified 4it+ fe4er o"ple o"ponents to onsider.

• Maintenane reuire"ents are easier to define and eeute, *y largely avoiding t+e need to

+ange one o"ponent to ao""odate t+e +ange in anot+er reuire"ent.

4.8Understand the Input and Output Messages

It s+ould *e possi*le to ea"ine t+e Funtional Speifiation and deter"ine 4+at t+e input is, and

4+at t+e output 4ould *e. Fro" t+is standpoint, t+e )M "essage flo4 an *e regarded as t+einstru"ent to onvert t+e input "essage into output "essagesB.

4.9Determine how many Message Flows are needed

First, at an appliation syste" level, it "ust *e deter"ined +o4 "any flo4s 4ill *e reuired for aninterfae. ut of t+is deter"ination, it 4ill *e possi*le to deter"ine +o4 "any types of "essagesa flo4 "ust +andle. So"eti"es t+ere is Cust one input "essage for"at and one output "essage


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for"at. t+er ti"es t+ere are "ultiple "essages for a given flo4 and t+ere "ust *e logi 4it+int+e flo4 to sort t+e" out.

4.10Complete the processing with as few nodes as possible

8+e "ost funda"ental reo""endation to onsider 4+en 4riting a "essage flo4 is to *e asonise as possi*le. 8+ere is a perfor"ane ost assoiated 4it+ passing t+roug+ ea+ of t+e*uilt-in nodes of )M, so it is *est to 4rite "essage flo4s in as fe4 nodes as possi*le.

In ot+er 4ords, t+ere s+ould *e as fe4 as possi*le nodes *et4een t+e input and output for"atsfor a given *usiness reuire"ent.

4.11Message Routing within a flow

!outing 4it+in t+e flo4 s+ould *e "ini"ied 4+ere possi*le. )+en routing is reuired, t+en t+erule a*out "ini"iing t+e nu"*er of nodes still applies.

For a nu"*er of reasons, so"e "essage flo4s proess "ore t+an one "essage type. In t+is

ase it is i"portant to understand t+e distri*ution of t+ese different "essage types and t+eir i"portane so t+at t+e "ost ritial or "ost freuent "essages go t+roug+ t+e +eapest pat+G i.e.t+e one 4it+ fe4est and si"plest nodes.

)+en "ore t+an one "essage is proessed in a flo4, or 4+en t+ere is a reuire"ent for dyna"ilogi inside a flo4 *ased on "essage ontent, t+ere are at least t4o 4ays to diret t+e proessinglogi inside t+e flo4.

ne 4ay is t+roug+ t+e use of !oute8o/a*el node. 8+is node "a>es use of t+e Destination/istarray of t+e /oalnviron"ent 8ree of a "essage flo4. )+en t+e "essage arrives, t+eDestination/ist is populated aording to t+e *usiness reuire"ent, and t+e !oute8o/a*el and/a*el nodes are used to diret su*seuent proessing.

Anot+er 4ay is *y using t+e Filter node. ne or "ore Filter nodes ea+ ontaining a oolean filter epression is set up to ontrol logi *ran+es. If t+ere are "any possi*le pat+s, t+e Filter nodesan *e set up a asade, 4it+ t+e "ost o""on "essage *eing direted along t+e earliest pat+.

8+e ost of using t+e Destination/ist is in setting it up in t+e first plae. 8+e ost of using Filters isin t+e nu"*er of nodes t+at are reuired for a o"ple routing evaluation. ne again, it isi"portant to "ini"ie t+e nu"*er of routing 4it+in a "essage flo4 as "u+ as possi*le.

Anot+er variation of t+e routing t+e"e is to deliver data to one or "ore destination syste"s. Int+is senario, it is desira*le to allo4 t+e target syste"s to *e identified t+roug+ a data*ase ta*ledriven "e+anis".

4.12SubFlows

Message Flo4s an *e divided into Su*Flo4s. ssentially, a Su*flo4 is a seuene of nodes t+at

*egins 4it+ an Input node and ends in an utput node. 8+e o*Cet of using Su*Flo4s is t+atfuntions an *e logially segregated in a 4ay t+at inreases "aintaina*ility and offersopportunity for reuse.

8+e use of Su*Flo4s does not +ave an adverse perfor"ane effet *eause at deploy ti"e t+eyare si"ply folded into t+e flo4 to 4+i+ t+ey are assigned. It is i"portant t+at t+e overall nu"*er of nodes s+ould not *e inreased 4+en using Su*Flo4s.


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4.13Transactionality and Persistence

As a rule, all "essages s+ould *e +andled as a 8ransation. In t+e Input, utput and o"putenodes, t+e 8ransationality s+ould al4ays *e set to EAuto"ati. 8+is pratie allo4s t+e)e*Sp+ere M; "essage attri*utes to ontrol t+e 8ransationality of t+e flo4G i.e. if a "essage is

read fro" a ueue 4it+ an attri*ute of E'ersistent, )I M 4ill supply t+e appropriate logging toguarantee t+e 8ransationality of t+e "essage.

It "ust *e onsidered t+at over+ead is inurred *y "a>ing a "essage transational. 8+is isaused *y t+e need to save all t+e data neessary to ena*le a roll *a> s+ould a failure onditionour in a "essage flo4.

4.14Use of CARDINALITY

8+e use of t+e A!DI9A/I8: funtion s+ould *e restrited to "ini"u" as it reuires t+e parser to proess a large portion of t+e "essage and t+ere*y +indering perfor"ane. 8+is *uilt-infuntion s+ould not *e used inside a loop unless it is inevita*le.

4.15ESQL REFERENCE Variable

!eferene varia*les an *e used in S;/ to store a part or an entire "essage tree loation andan *e t+oug+t of as *eing si"ilar to a &HH pointer to a "essage ele"ent. 8+e use of !F!9 varia*le is reo""ended in S;/ for t4o reasons#

• 8+ey redue oding onsidera*ly, espeially, 4+en large "essage tree 4it+ deep +ierar+y

+as *een defined.

• 8+ey "a>e S;/ "ore effiient 4+en used appropriately.

!eferene varia*les an *e used to store loations in any type of "essage tree Input!oot,utput!oot, /oalnviron"ent, nviron"ent, etB.

4.16Use of MOVE & LASTMOVE

8+e M


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4.17Backout Processing Considerations

)+en an eeption is t+ro4n 4it+in a "essage flo4 and is not aug+t *y inlusion of a 8ryat+9ode, t+e Input 9ode for t+e "essage flo4 at+es it. If t+e at+ ter"inal of t+e M;Input 9odeis onneted, t+e "essage is propagated to t+is ter"inal and is proessed aording to t+e

"essage flo4 logi.If t+e at+ ter"inal of t+e M;Input 9ode is not onneted, t+e transation is rolled *a>. If t+e"essage 4as read under a synpoint t+e original re"ains in t+e ueue *ut )e*Sp+ere M;inre"ents t+e M;MD a>out ount. 8+e M;Input 9ode t+en reads t+e "essage one again.

8+e M;MD a>out ount is ea"ined *efore t+e "essage is proessed again. If it is not erot+en it i"plies t+at t+e "essage reeived *y t+e "essage flo4 is a *a>ed out "essage and t+e*ro>er t+en perfor"s *a>out proessing.

• If t+e M;MD *a>out ount is less t+an t+e a>out !eueue 8+res+old attri*ute speified in

t+e ueue definition, t+e "essage is propagated t+roug+ t+e output ter"inal of t+e M;Input9ode for nor"al proessing one again.

• If t+e M;MD *a>out ount is not less t+an t+e a>out !eueue 8+res+old attri*ute

speified in t+e ueue definition, t+e "essage is propagated t+roug+ t+e Failure ter"inal of t+e M;Input 9ode.

• If t+e Failure ter"inal is 4ired t+en it follo4s t+at pat+ *ut, if it is not 4ired t+e a>out

!eueue 9a"e attri*ute is loo>ed for and if a ueue na"e found in t+is attri*ute, t+e"essage is put into t+at ueue.

• If no na"e is speified in t+e a>out !eueue 9a"e attri*ute, t+e "essage is 4ritten to t+e

default Dead /etter ;ueue defined for t+e ueue "anager.

• If t+e "essage ould not *e 4ritten to t+e Dead /etter ;ueue t+en it re"ains in t+e Input

;ueue.

4.18WBI MB Message Flow Standard Unit Test Conditions8+e follo4ing are t+e standard nit 8est onditions t+at s+ould *e onsidered *y a developer 4+ile perfor"ing nit 8est on an interfae#

• )+en a valid 8est Data is passed t+roug+ t+e "essage flo4 one or "ore output "essagesB

are reated on t+e output ueuesB.

• )+en an invalid 8est Data is passed t+roug+ t+e "essage flo4 t+e "essage is propagated to

t+e error +andling ueue for error proessing.

• All fields of t+e output "essage are of orret lengt+ and +ave *een orretly for"atted

aording to t+e reuire"ents.

• )+ere t+e "essage +as repeating fields or struture, t+e interfae 4or>s orretly for *ot+

single and "ultiple instanes of t+e field or struture.

• )+ere t+e "essage +as an optional field or struture, t+e interfae 4or>s orretly for *ot+

4it+ and 4it+out t+e field or struture in t+e "essage.


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. ESQL Development Guidelines

5.1Line Length

It "ust *e possi*le to vie4 an S;/ file in a tet editor 4it+out srolling to t+e rig+t, and to print itout on A% portrait 4it+out line trunation or 4rapping. In pratie, t+is "eans to li"it a line to a*oundary of 50 +araters approi"ately.

5.2Wrapping Lines

)+en an epression does not fit in a single line, it is reo""ended to *rea> t+e line aording tot+e follo4ing general priniples#

• rea> after a o""a.

• rea> after an operator.

• 'refer +ig+-level *rea>s to lo4-level *rea>s.

• Align t+e ne4 line 4it+ t+e *eginning of t+e sa"e level epression on t+e previous line.

If t+e a*ove rules lead to onfusing ode or ode t+at is suis+ed up against t+e rig+t "argin, Custindent 5 spaes instead.

5.3Comments

8+e S;/ ode s+ould *e self-eplanatory as far as possi*le, for ea"ple, *y use of "eaningfulvaria*le na"es. o""ents are needed +o4ever, to eplain 4+at t+e S;/ ode is doing or 4+y

is it doing t+at 4ay if it is not o*vious. nderlying assu"ptions s+ould *e noted.

se t+e "ore standard for"at E& o""ent & for +eaders and "ulti-line o""ents, and E --o""ent for single line o""ents. o""ents "ust *e in o+erent gra""atial nglis+ starting4it+ a apital letter. Multiline o""ents s+ould *e a*ove t+e line of odes t+ey refer to, indentedto t+e sa"e level as t+e ode itself and *e preeded *y a *lan> line.

A o""ent is reo""ended for ea+ logi onstrut as t+is tends to *e 4+ere *usiness logi an*e eplained.

5.4Flower Box Comments

Flo4er *o o""ents "ust appear at t+e start of every S;/ File, Module, 'roedures and

Funtions. 8+e for"at s+ould *e as follo4s#ESQL /ile /lo0er Bo1

/**********************************************************************

* COPYRIGHT. . ALL RIGHTS RESERVED. NO PART OF *

* THIS SOURCE CODE MAY BE REPRODUCED, STORED IN A RETRIEVAL SYSTEM, OR*

* TRANSMITTED, IN ANY FORM BY ANY MEANS, ELECTRONIC, MECHANICAL, PHOTO*


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* COPYING, RECORDING OR OTHERWISE, WITHOUT THE PRIOR WRITTEN PERMISS- *

* ION OF *

**********************************************************************/

ESQL Module /lo0er Bo1

/**********************************************************************

* Node Name: *

* Module Name: *

* Description: *

* *

* Version Date Author Description *

* =============== =========== =========== ============================*

*


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5.5Block Comments

lo> o""ents inside a state"ent s+ould *e indented to t+e sa"e level as t+e ode t+eydesri*e. A *lo> o""ent s+ould *e preeded *y a *lan> line to set it apart fro" rest of t+eode.

/*

* Here is a block comment

* They are usually more than one line long

* and are preceded by a blank line.

*/

SET OutputRoot.XML.MyMsg.MyFld01 = ‘Value01’;

SET OutputRoot.XML.MyMsg.MyFld02 = ‘Value02’;

SET OutputRoot.XML.MyMsg.MyFld03 = intValue03;

5.6Internal and End-of-Line Comments

S+ort o""ents an if neededB appear on a single line indented to t+e level of t+e ode t+atfollo4s. A *lan> line s+ould preede a single line o""ent.

-- Set Customer First Name

SET OutputRoot.XML.MyMsg.Customer.FirstName = ‘John’;

-- Set Customer Last Name

SET OutputRoot.XML.myMsg.Customer.LastName = ‘Smith’;


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/*

Old Code stuff.....

.....

*/

New Code stuff .....

.....

-- CR02577 End

5.8Statements

/ogial onstruts su+ as )3I/, IF, AS and data*ase ations s+ould +ave a o""entpreeding t+e". 8+ese are t+e *lo>s 4+ere *usiness logi is perfor"ed and t+e "ost li>elystu"*ling point 4+en it o"es to ot+ers trying to understand t+e ode.

Speifi rules applying to t+ese state"ents follo4s, alt+oug+ in "any iru"stanes, o""on

sense 4ill prevail.

.2( WH)LE Statement/*

* Comment here for the

* WHILE Block

*/

WHILE DO

END WHILE;

.2* )/ Statement/*


* IF-ELSE Block

*/

IF THEN

ELSEIF THEN

ELSE

END IF;


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.2+ #,SE Statement/*


* CASE Statement Block

*/

SET intGrade = CASE InputRoot.MyMsg.Student.Marks

WHEN > 90 THEN 1

WHEN > 80 THEN 2

WHEN > 70 THEN 3

WHEN > 60 THEN 4

ELSE 5

END;

.2- SELE# Statement/*


* INSERT Block

*/

SET Environment.Variables.EmpList[] =

(SELECT T.EMP_ID,

T.EMP_NAME,

T.EMP_AGE FROM Database.Schema.T_EMP AS T

WHERE T.EMP_ID IN (1, 2, 3, 4, 5)

AND T.EMP_AGE >= intMinAge);

.2. )NSE! Statement/*


* INSERT Block

*/

INSERT INTO Database.Schema.T_EMP

(EMP_ID,

EMP_NAME,

EMP_AGE)

VALUES intEmp_ID,


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chrEmpName,

intEmpAge;

.23 4pdate Statement

/** Comment here for the

* Update Block

*/

Update Database.Schema.T_Emp AS T

SET EMP_NAME = chrEmpName,

EMP_AGE = 25

WHERE T.EMP_ID = intEmpID;

.25 DELEE Statement/*


* DELETE Block

*/

DELETE FROM Database.Schema.T_EMP AS T

WHERE T.EMP_ID = intEmpId;

5.9Declarations

Delaration of varia*les "ust *e "ade at t+e *eginning of ea+ and every proedure or funtion.ne varia*le delaration per line is reo""ended. Delarations s+ould *e grouped *y varia*letype and a *lan> line s+ould separate t4o groups. Also it is reo""ended not to initialie avaria*le during delaration. Initialiation s+ould *e epliitly "ade as a separate assign"entstate"ent.

DECLARE intVar01 INTEGER;



DECLARE chrVar01 CHARACTER;

DECLARE chrVar02 CHARACTER;

DECLARE blnVar01 BOOLEAN;


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3 ,ppendi1 ( )mportant Structures

6.1MQMD – Message Descriptor

8+e M;MD struture ontains t+e ontrol infor"ation t+at ao"panies t+e appliation data4+en a "essage travels fro" one ueue to anot+er.

8+e follo4ing ta*le su""aries t+e fields in t+e struture#

/ield Description

StruId Struture Identifier


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riginal/engt+ /engt+ of original "essage

6.2MQRFH2 – Rules and Formatting Header8+e M;!F32 struture defines t+e layout of t+e rules and for"atting +eader. 8+is +eader an *eused to send string data t+at +as *een enoded using an JM/-li>e synta. It allo4s niodestring to *e transported 4it+out translations, and it an arry nu"eri data-types.

8+e follo4ing ta*le su""aries t+e fields in t+e struture#

/ield Description

StruId Struture Identifier


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!eplyIdentifier 8+e reply identifier

!eply'rotool 8+e reply protool


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5 ,ppendi1 * De'u% racin%

In t+e event of an error in a "essage flo4, a de*ug level trae s+ould *e set up for t+e flo4. 8+isis done 4it+ t+e +elp of a set of o""ands to generate t+e de*ug trae file for diagnostis.

1. pen a o""and pro"pt 4indo4.

2. eute t+e o""and "si+angetrae Kro>er 9a"eL -u -e Keution ?roup 9a"eL -lde*ug -f KMessage Flo4 9a"eL -r

$. eute t+e "essage flo4 4it+ t+e "essage t+at you 4ant to trae.

%. eute t+e o""and "sireadlog Kro>er 9a"eL -u -e Keution ?roup 9a"eL -l de*ug-f KMessage Flo4 9a"eL -o K8e"porary File 9a"eL

(. eute t+e o""and "sifor"atlog @i K8e"porary File 9a"eL -o K8rae File 9a"eL

pen t+e generated 8rae file in a tet editor and perfor" diagnosis.


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2 , Sample ESQL

/**********************************************************************

* COPYRIGHT. ALL RIGHTS RESERVED. NO PART OF *

* THIS SOURCE CODE MAY BE REPRODUCED, STORED IN A RETRIEVAL SYSTEM, OR*

* TRANSMITTED, IN ANY FORM BY ANY MEANS, ELECTRONIC, MECHANICAL, PHOTO*

* COPYING, RECORDING OR OTHERWISE, WITHOUT THE PRIOR WRITTEN PERMISS- *

* ION OF *

**********************************************************************/

/**********************************************************************

* Node Name: Get Employee Information *

* Module Name: IDD111_EmployeeInfo *

* Description: This module searches for information about the*

* Employee from the Employee Database. *

* *


* =============== =========== =========== ============================*

* 1.00 25-Feb-2006 A. Program The initial version. *

**********************************************************************/

CREATE COMPUTE MODULE IDD111_EmployeeInfo

/****************************************************************

* Function Name: Main *

* Input Parameters: None *

* Output Parameters: Boolean Return *

* Description: The Main entrypoint to the module *


* =============== =========== =========== ======================*

* 1.00 25-Feb-2006 A. Program The initial version *

*****************************************************************************/

CREATE FUNCTION Main() RETURNS BOOLEAN

BEGIN

-- Copy input headers to output

CALL prcCopyMessageHeaders();


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-- Create the output message

CALL prcCreateOutputMessage();

-- Return success

RETURN TRUE;

END;

/****************************************************************

* Procedure Name: prcCopyMessageHeaders *


* Output Parameters: None *

* Description: Copies input message headers to *

* the output message *


* =============== =========== =========== ======================*


*****************************************************************************/

CREATE PROCEDURE prcCopyMessageHeaders()

BEGIN

DECLARE intIdx INTEGER; -- An Index Pointer

DECLARE intCounter INTEGER; -- A counter

-- Initialize Index to 1

SET intIdx = 1;

-- Initialize counter to cardinality of InputRoot

SET intCounter = CARDINALITY(InputRoot.*[]);

/*

Iterate through each subtree of InputRoot and copy the

Sub-tree to the OutputRoot until the Last one.

*/

WHILE intIdx < intCounter DO

SET OutputRoot.*[intIdx] = InputRoot.*[intIdx];


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SET intIdx = intIdx + 1;

END WHILE;

END;

/****************************************************************

* Procedure Name: prcCreateOutputMessage *


* Output Parameters: None *

* Description: Creates the Output Message *


* =============== =========== =========== ======================*


*****************************************************************************/

CREATE PROCEDURE prcCreateOutputMessage()

BEGIN

DECLARE chrEmpId CHARACTER; -- Employee Id

-- Initialize chrEmpId

SET chrEmpId = InputRoot.XML.Employee.Id;

-- Check that the EmpId is not NULL to proceed

IF chrEmpId IS NULL THEN

-- Throw an Exception

THROW USER EXCEPTION VALUES (‘The Employee Id

Received in the Input is NULL’);

END IF;

-- Retrieve the Employee Info from Database

SET OutputRoot.XML.Employee.EmployeeInfo[] =

(SELECT T.EMP_ID AS EmployeeID,

T.EMP_NAME AS EmployeeName,

T.EMP_DOJ AS EmployeeDOJ,

T.EMP_CURR_SAL AS EmployeeSalary

FROM Database.HRM.T_EMP_MASTER AS T

WHERE T.EMP_ID = chrEmpId);


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-- Check If any record is retrieved

IF CARDINALITY(OutputRoot.XML.Employee.EmployeeInfo[])

IS NULL THEN

-- Throw an Exception

THROW USER EXCEPTION VALUES (‘Employee Number ‘ ||

chrEmpId || ‘ does not exist.’);

END IF;

END;

END MODULE;


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Documents

WMB Best Practices and ESQL Development Guidelines