// Execute an SQL statement against the data source
func (ds DataSource) ExecuteSQL(sql string, filter Geometry, dialect string) Layer {
cSQL := C.CString(sql)
defer C.free(unsafe.Pointer(cSQL))
cDialect := C.CString(dialect)
defer C.free(unsafe.Pointer(cDialect))
layer := C.OGR_DS_ExecuteSQL(ds.cval, cSQL, filter.cval, cDialect)
return Layer{layer}
}
func (ds *DataSource) Query(query string) (*Layer, error) {
// create select query if it is only a where statement
if !strings.HasPrefix(strings.ToLower(query), "select") {
layer, err := ds.Layer()
if err != nil {
return nil, err
}
layerDef := C.OGR_L_GetLayerDefn(layer.v)
name := C.OGR_FD_GetName(layerDef)
query = fmt.Sprintf("SELECT * FROM %s WHERE %s", C.GoString(name), query)
}
queryc := C.CString(query)
defer C.free(unsafe.Pointer(queryc))
layer := C.OGR_DS_ExecuteSQL(ds.v, queryc, nil, nil)
if layer == nil {
return nil, lastOgrError("unable to execute query '" + query + "'")
}
return &Layer{layer}, nil
}