UltraLite for MobileVB User's Guide
UltraLite for MobileVB API Reference
ULColumn class
GetByteChunk ( _
offset As Long, _
data As Long, _
data_len As Long, _
filled_len As Long _
) As Boolean
Member of UltraLiteAFLib.ULColumn
Gets data from a TypeBinary or TypeLongBinary column.
offset The offset into the underlying array of bytes. The source offset must be greater than or equal to 0, otherwise a ulSQLE_INVALID_PARAMETER error will be raised.
data A pointer to an array of bytes. To get the pointer to the array of bytes, use the Visual Basic VarPtr() function.
data_len The length of the buffer, or array. The data_len must be greater than or equal to 0.
filled_len This is an OUT parameter. After the method is called, it indicates how many bytes were fetched with valid data. If the size of BLOB data is unknown in advance, it is fetched using a fixed-length chunk - one chunk at a time. The last chunk fetched can be smaller than chunk size, so filled_len informs how many bytes of valid data exist in the buffer.
True if this column value contains more data
False if there is no more data for this column in the database.
| Error | Description |
|---|---|
| ulSQLE_CONVERSION_ERROR | The error occurs if the column data type isn't BINARY or LONG BINARY. |
| ulSQLE_INVALID_PARAMETER |
The error occurs if the column data type is BINARY and the offset is not 0 or 1, or, the data length is less than 0.
The error also occurs if the column data type is LONG BINARY and the offset is less than 1 . |
In the following example, edata is a column name. If the data_len parameter passed in is larger than the actually array size, a General Protection Fault occurs.
Dim filled As Long
Dim more_data As Boolean
Dim data (1 to 512) As Byte
more_data = table.Column("edata").GetByteChunk(0, _
VarPtr(data(1)), 512, filled)