XPath-Beispiel zur Darstellung der unterschiedlichen SELECT-Typen

Beispiel XML-Datei (XMLFactoryXY.xml)

<?xmlversion="1.0" encoding="utf-8" ?>
<Factory_XY>
 <Name>Sample Factory XY</Name>
 <Factory_Info>
 <Street>Samplestreet 25</Street>
 <City>33415 Verl</City>
 <Country>Germany</Country>
 <Office_Count>1</Office_Count>
 <Employe_Count>6</Employe_Count>
 <Manager>Max Mustermann</Manager>
 </Factory_Info>
 <Employees>
 <Employeeid="10001" name="Julia Kingston" department="Development" position="Worker" hired="2001-08-01" />
 <Employeeid="10002" name="Jens Marx" department="Import" position="Worker" hired="2003-08-01" />
 <Employeeid="10003" name="Justus Kaiser" department="Export" position="Worker" hired="2003-08-01" />
 <Employeeid="10004" name="Marc Klein" department="Production" position="Worker" hired="2005-08-01" />
 <Employeeid="10005" name="Matt Bloomberg" department="Production" position="Worker" hired="2005-08-01" />
 <Employeeid="10006" name="Frida Hundt" department="Production" position="Worker" hired="2010-08-01" />
 </Employees>
</Factory_XY>

Struktur ST_FactoryInfo

TYPEST_FactoryInfo :
STRUCT
 sStreet       : T_MaxString;
 sCity         : T_MaxString;
 sCountry      : T_MaxString;
 sOffice_Count : T_MaxString;
 sEmploye_Count: T_MaxString;
 sManager      : T_MaxString;
END_STRUCT
END_TYPE 

Struktur ST_Employee

TYPEST_Employee :
STRUCT
 sID          : T_MaxString;
 sName        : T_MaxString;
 sDepartment  : T_MaxString;
 sPosition    : T_MaxString;
 sHired       : T_MaxString;
END_STRUCT
END_TYPE 

MAIN-Programm

PROGRAM MAIN 
VAR
     bSTART    : BOOL;
     R_TRIG1   : R_TRIG;
     
     nState    : INT;

     sXPath    : T_MaxString;
     
     fbDBRecordArraySelect : FB_DBRecordArraySelect;
     
     bBusy_ReadFactoryName : BOOL;
     bError_ReadFactoryName: BOOL;
     nErrID_ReadFactoryName: UDINT;
     
     bBusy_ReadFactoryInfo : BOOL;
     bError_ReadFactoryInfo: BOOL;
     nErrID_ReadFactoryInfo: UDINT;
     
     bBusy_ReadEmployee    : BOOL;
     bError_ReadEmployee   : BOOL;
     nErrID_ReadEmployee   : UDINT;
     
     stSQLState            : ST_DBSQLError;
     
     sFactoryName          : T_MaxString;
     stFactoryInfo         : ST_FactoryInfo;
     aEmployees            : ARRAY [1..10] OF ST_Employee;
END_VAR 

R_TRIG1(CLK:=bSTART);
IF R_TRIG1.Q THEN
     bSTART:=FALSE;
     fbDBRecordArraySelect(bExecute:=FALSE);
     nState:=1;
END_IF

CASE nState OF
     0://IDLE
         ;
     1://Read Factory Name
         sXPath:= 'XPATH#Factory_XY/Name';
         fbDBRecordArraySelect(
             sNetID           := , 
             hDBID            := 7, 
             pCmdAddr         := ADR(sXPath), 
             cbCmdSize        := SIZEOF(sXPath), 
             nStartIndex      := 0, 
             nRecordCount     := 1, 
             pDestAddr        := ADR(sFactoryName), 
             cbRecordArraySize:= SIZEOF(sFactoryName), 
             bExecute         := TRUE, 
             tTimeout         := T#15S, 
             bBusy             => bBusy_ReadFactoryName, 
             bError            => bError_ReadFactoryName, 
             nErrID            => nErrID_ReadFactoryName, 
             sSQLState         => stSQLState, 
             nRecords          => );
             
         IF NOT bBusy_ReadFactoryName THEN
             fbDBRecordArraySelect(bExecute:=FALSE);
             IF NOT bError_ReadFactoryName THEN
                 nState        :=2;
             ELSE
                 nState        :=255;
             END_IFEND_IF
     2://Read Factory Info
         sXPath                 := 'XPATH#Factory_XY/Factory_Info';
         fbDBRecordArraySelect(
             sNetID            := , 
             hDBID             := 7, 
             pCmdAddr          := ADR(sXPath), 
             cbCmdSize         := SIZEOF(sXPath), 
             nStartIndex       := 0, 
             nRecordCount      := 1, 
             pDestAddr         := ADR(stFactoryInfo), 
             cbRecordArraySize := SIZEOF(stFactoryInfo), 
             bExecute          := TRUE, 
             tTimeout          := T#15S, 
             bBusy              => bBusy_ReadFactoryInfo, 
             bError             => bError_ReadFactoryInfo, 
             nErrID             => nErrID_ReadFactoryInfo, 
             sSQLState          => stSQLState, 
             nRecords           => );
             
         IF NOT bBusy_ReadFactoryInfo THEN
             fbDBRecordArraySelect(bExecute:=FALSE);
             IF NOT bError_ReadFactoryInfo THEN
                 nState         :=3;
             ELSE
                 nState         :=255;
             END_IF
         END_IF
     3://Read Employees
         sXPath                  := 'XPATH#Factory_XY/Employees/Employee';
         fbDBRecordArraySelect(
             sNetID             := , 
             hDBID              := 7, 
             pCmdAddr           := ADR(sXPath), 
             cbCmdSize          := SIZEOF(sXPath), 
             nStartIndex        := 0, 
             nRecordCount       := 10, 
             pDestAddr          := ADR(aEmployees), 
             cbRecordArraySize  := SIZEOF(aEmployees), 
             bExecute           := TRUE, 
             tTimeout           := T#15S, 
             bBusy               => bBusy_ReadEmployee, 
             bError              => bError_ReadEmployee, 
             nErrID              => nErrID_ReadEmployee, 
             sSQLState           => stSQLState, 
             nRecords            => );
             
         IF NOT bBusy_ReadEmployee THEN
             fbDBRecordArraySelect(bExecute:=FALSE);
             IF NOT bError_ReadEmployee THEN
                 nState          :=0;
             ELSE
                 nState          :=255;
             END_IFEND_IF
     255://Error State
         ;
END_CASE

Mit einer positiven Flanke an der Variable "bStart" werden die XPath-Kommandos abgesetzt und die einzelnen Elemente aus der XML-Datei gelesen. Die Ergebnisse stehen in den Variablen "sFactoryName", "stFactoryInfo" und "aEmployees".

Voraussetzungen