Class RDbColReadStream

RDbColReadStream

Support

Supported from 5.0

Description

Allows any column value to be read as stream data.

Note that this is the only way to extract the contents of a Long column from a rowset.

Only one column in a rowset object can be opened for reading as a stream at a time, and while it is open no column in the same rowset object may be set using RDbColWriteStream.

Null columns result in a read stream with no data. Small numeric columns are maintained in memory as 32-bit values; hence reading a Uint8 column as a stream results in 4 bytes of stream data, not 1.

Derivation

RDbColReadStream Allows any column value to be read as stream data RReadStream The read stream interface

Defined in RDbColReadStream:
OpenL(), OpenLC()

Inherited from RReadStream:
Attach(), Close(), Detach(), Pop(), PushL(), ReadInt16L(), ReadInt32L(), ReadInt8L(), ReadL(), ReadReal32L(), ReadReal64L(), ReadUint16L(), ReadUint32L(), ReadUint8L(), Release(), Source()

void OpenL(const RDbRowSet& aView,TDbColNo aCol);

Description

Opens the column with the specified ordinal in the specified current row in the rowset. The row must have previously been read into the rowset using RDbRowSet::GetL().

Parameters

const RDbRowSet& aView The rowset which has the row and column to be read. TDbColNo aCol The column ordinal of the column to be read

Leave codes

The function can leave with one of the DBMS database error codes.

See also:

• Additional DBMS database error codes

void OpenLC(const RDbRowSet& aView,TDbColNo aCol);

Description

Opens the column with the specified ordinal in the specified current row in the rowset and puts a pointer to the column on the cleanup stack.

The row must have previously been read into the rowset using RDbRowSet::GetL().

Parameters

const RDbRowSet& aView The rowset which has the row and column to be read. TDbColNo aCol The column ordinal of the column to be read.

Leave codes

The function can leave with one of the DBMS database error codes.

See also:

• Additional DBMS database error codes