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GetData

procedure GetData(const aDataSet: TvxClientDataSet;
  const aSQL: string);

Example​

procedure ScriptEvent(var Value: variant);
begin
  GetData(Data,
    'select ItemID, Status from ExampleQueue where Status = ''Ready''');
  Value := Data.RecordCount;
end;

Usage​

GetData opens SQL into a client dataset using the Velox Data database connection.

Parameters

NameTypeDescription
aDataSetTvxClientDataSet, const referenceMutable dataset to close, clear, bind to SQLD and open.
aSQLstring, constQuery text expected to return a cursor. Parameter recognition is disabled.

Returns

No status. A successful call leaves aDataSet.Active = True; an empty cursor is not a failure.

Security and data safety

The SQL text is direct and fully logged. Do not concatenate untrusted input, and select only columns/rows required by the map. The function does not establish read-only behaviour; database permissions and statement text determine what the connection can do, although opening Active is intended for cursor-returning SQL.

Additional Technical Info​

GetData closes and rebinds a supplied client dataset, then opens a query on the Velox Data database connection (gSystemConnection.SQLD).

The objects are fictional. The example is source-reviewed and was not executed.

Implementation

The method closes the dataset, disables SQLDataSet.ParamCheck, clears FieldDefs, assigns gSystemConnection.SQLD, sets and logs CommandText, and opens it with Active := True. Unlike ExecSQLData, this wrapper does not explicitly call vxStartTransaction.

Side effects and errors

Existing fields, cursor position, edits, SQL and connection are discarded. Exceptions are caught, reduced to a key SQL error line for the message, logged with the script/full SQL context and suppressed. There is no Boolean result; after failure the dataset can be inactive and partially rebound.

Performance and concurrency

Open/fetch is synchronous. Large results can delay the map and consume client-dataset memory; later cursor operations may perform further fetches. The same dataset must not be rebound while another consumer uses it.

Related entries

  • GetConfig targets Velox configuration data.
  • ExecSQLData explicitly starts/reuses an SQLD transaction before opening.
  • ExecSQL executes non-query SQLD statements.

External references

Created 2026-07-15