ReadAsStruct

This method reads a specified number of records from the buffered result data. A structure or an array of a structure is specified in which the data is to be written. The data type schema of this structure should correspond as closely as possible to that of the read data. The variable names are compared with those of the record. A validation makes it possible to detect deviations and respond to them.

If there is a requirement to use different names in the database and in the PLC, the names can be described in the structure with the attribute 'ElementName' with the assigned name from the database.

Syntax

METHOD ReadAsStruct: BOOL
VAR_INPUT
    nStartIndex: UDINT := 0;
    nRecordCount: UDINT := 1;
    pData: POINTER TO BYTE;
    cbData: UDINT;
    bValidate: BOOL := FALSE; 
    pNoSQLValidation : POINTER TO FB_NoSQLValidationEvt;
    bDataRelease: BOOL := TRUE;
END_VAR

Inputs

Name	Type	Description
nStartIndex	UDINT	Indicates the index of the first record to be read.
nRecordCount	UDINT	Indicates the number of records to be read.
pData	POINTER TO BYTE	Address of the structure array into which the records are to be written.
cbData	UDINT	Indicates the size of the structure array in bytes.
bValidate	BOOL	Return data are compared with the pData structure array and adjusted if necessary.
pNoSQLValidation	POINTER TO FB_NoSQLValidationEvt	Address of the function block FB_NoSQLValidationEvt that provides further information for validating the call.
bDataRelease	BOOL	Releases the cached data.

Return value

Name	Type	Description
ReadAsStruct	BOOL	Displays the status of the method. Returns TRUE as soon as the method execution is finished, even in the event of an error.

Sample:

VAR
    fbNoSQLResult: FB_NoSQLResultEvt(sNetID := '', tTimeout := T#5S);
    aRead : ARRAY[0..2] OF ST_MyDataStruct;
    fbNoSQLValidation : FB_NoSQLValidationEvt(sNetID := '', tTimeout := #5S);
END_VAR

IF fbNoSQLResult.ReadAsStruct(
    nStartIndex:= 0, 
    nRecordCount:= 3, 
    pData:= ADR(aRead), 
    cbData:= SIZEOF(aRead), 
    bValidate:= TRUE, 
    pNoSQLValidation:= ADR(fbNoSQLValidation), 
    bDataRelease:= TRUE) 
THEN
    IF fbNoSQLResult.bError THEN
        TcMessage := fbNoSQLResult.ipTcResult;
        nstate := 255; 
    ELSE
        nstate := nstate+1;
    END_IF    
END_IF