ImportRowFromJson

method (DataWindows)

Description

Inserts a data row from a JSON string into a DataWindow control,
DataStore object, or DataWindowChild object. The status of the inserted
data row is NotModified!.

The JSON string that can be imported by this function must be a
one-level plain JSON string. For details, see Plain JSON:
one-level structure in Application Techniques.

This function will fail to import data properly, if the DataWindow
is in query mode.

Applies to

DataWindow type	Method applies to
PowerBuilder	DataWindow control, DataWindowChild object, and DataStore object, except for those with the Composite, Crosstab, OLE 2.0, or RichText presentation styles.

Syntax

PowerBuilder

long dwcontrol.ImportRowFromJson( string json, long row {, ref string error} {, DWBuffer dwbuffer})

1	long dwcontrol.ImportRowFromJson( string json, long row {, ref string error} {, DWBuffer dwbuffer})

Argument	Description
dwcontrol	A reference to a DataWindow control, DataStore, or DataWindowChild.
json	A string specifying the JSON data. The JSON string must be in the plain format which must have only one level (cannot be two or more) and must be an object (cannot be an array).
row	A long value identifying the row before which you want to insert a row. To insert a row at the end, specify 0, or a negative value, or a value greater than the row count in the DataWindow buffer.
error (optional)	A variable into which the returned warning or error message will be placed. When there are a large amount of error messages, the error information will only display the total number of errors, and the detailed message of the first 10 errors. The import warning caused by data type mismatch will not affect the return value of this function; although the data of the mismatched columns will not be imported, the rest columns (even only one column) that are matched will be imported successfully; and that row will be regarded as a successful import and counted into the return value. The import error caused by DW presentation style mismatch, invalid arguments etc. will be regarded as a failure, and represented by a negative return value of this function, instead of being placed into this variable. See the Return Value section for more. Most of the messages placed into this variable are warnings (such as data type mismatch) rather than errors. Developers can adjust the JSON data according to the message or simply ignore the message if the problematic column is not critical and the corresponding DataWindow column can be left blank.
dwbuffer (optional)	A value of the dwBuffer enumerated datatype identifying the DataWindow buffer from which you want to import the data. For a list of valid values, see DWBuffer. If not specified, imports the JSON data to the Primary! buffer. If specified, imports the JSON data to the specified buffer.

Return value

Long. Returns 1 if the data row was added successfully and one of
the following negative integers if an error occurs.

-1 — General error.

-3 — Invalid argument.

-4 — Invalid JSON.

-5 — JSON format error.

-6 — Unsupported DataWindow presentation style for import.

-7 — Error resolving DataWindow nesting.

The method returns null if any of the following:

any argument’s value is null
the DataWindow object (dataobject) is invalid

Usage

There is no forced conversion between strings and numbers. For
example, the number 123 in JSON string will not be imported into the
DataWindow column of char(10) type. For such case, a data type mismatch
warning will be recorded in the error argument.

A boolean value (true or false) will be converted to 0 or 1 when
imported from the JSON string to the DataWindow; however, 0 or 1 will not
be converted to a boolean value (true or false) when exported from the
DataWindow to the JSON string.

If the string length in JSON is larger than the string length in
DataWindow, the string will be truncated when imported into the
DataWindow. For example, JSON string [{“name”:”TestForTrancate”}] is
imported as “Test” if the data type of DataWindow column “name” is
char(4).

When the number value is imported from the JSON string to the
DataWindow column of number data type (with uncertain precision), the
value will have uncertain decimals, for example, 6.78 becomes
6.78000020980835 after imported from the JSON string to the
DataWindow.

Example

The following example imports two rows, one before the first row and
the other before the last row.

String ls_Json = '{"dept_id":1900,"dept_name":"Test send patch request42","dept_head_id":"test"}'
String ls_Error
Integer li_ImportJsonReturn

//Inserts a row before the first row
//Note that the column name and data type between JSON string and DataWindow must match
li_ImportJsonReturn = dw_Data.ImportRowFromJson( ls_Json, 1, ls_Error)
If Trim(ls_Error) &lt;&gt; "" Then
 //Prints the value of ls_Error. 
 //The data type of the last column between JSON string and DataWindow does not match
 //so there will be an error message here.
End If

ls_Json = '{"dept_id":1900,"dept_name":"Test send patch request42","dept_head_id":1}'
//Inserts a row before the last row
//Note that the column name and data type between JSON string and DataWindow must match
li_ImportJsonReturn = dw_Data.ImportRowFromJson( ls_Json, 0, ls_Error, Primary!)
If Trim(ls_Error) &lt;&gt; "" Then
 //Prints the value of ls_Error
End If

String ls_Json = '{"dept_id":1900,"dept_name":"Test send patch request42","dept_head_id":"test"}'

String ls_Error

Integer li_ImportJsonReturn

//Inserts a row before the first row

//Note that the column name and data type between JSON string and DataWindow must match

li_ImportJsonReturn = dw_Data.ImportRowFromJson( ls_Json, 1, ls_Error)

If Trim(ls_Error) <> "" Then

//Prints the value of ls_Error.

//The data type of the last column between JSON string and DataWindow does not match

//so there will be an error message here.

End If

ls_Json = '{"dept_id":1900,"dept_name":"Test send patch request42","dept_head_id":1}'

//Inserts a row before the last row

//Note that the column name and data type between JSON string and DataWindow must match

li_ImportJsonReturn = dw_Data.ImportRowFromJson( ls_Json, 0, ls_Error, Primary!)

If Trim(ls_Error) <> "" Then

//Prints the value of ls_Error

End If

See also

ExportRowAsJson

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August 21, 2023

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ImportRowFromJson

method (DataWindows)

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