com.sparsity.sparksee.gdb.QueryStream Class Reference

Query stream interface. More...

Public Member Functions
bool	Fetch (com.sparsity.sparksee.gdb.ValueList list)
	Gets the next row and moves the iterator forward.
bool	Prepare (com.sparsity.sparksee.gdb.ValueList list)
	Prepares the stream before it is started.
bool	Start (com.sparsity.sparksee.gdb.ResultSetList list)
	Starts the stream.

Detailed Description

Query stream interface.

A QueryStream is the interface between the application and the STREAM operator. When the operator starts inside a Query, the method is prepared with query-defined arguments. Then, if there are input operations, the STREAM operator builds the ResultSets and starts the iteration. Finally, the operator fetches rows until no more are available.

Application exceptions must be cached by the subclass that implements the interface.

Author

Sparsity Technologies http://www.sparsity-technologies.com

Member Function Documentation

Fetch()

bool com.sparsity.sparksee.gdb.QueryStream.Fetch

(

com.sparsity.sparksee.gdb.ValueList

list

)

Gets the next row and moves the iterator forward.

The end of sequence is denoted by returning TRUE with an empty row. A valid row must contain as many values (even NULL) as expected by the query.

Parameters

list	[out] Storage for the new rows

Returns

TRUE if there is a row or end of sequence, FALSE on error

Prepare()

bool com.sparsity.sparksee.gdb.QueryStream.Prepare

(

com.sparsity.sparksee.gdb.ValueList

list

)

Prepares the stream before it is started.

Parameters

list	[in] Optional list of arguments

Returns

FALSE on error

Start()

bool com.sparsity.sparksee.gdb.QueryStream.Start

(

com.sparsity.sparksee.gdb.ResultSetList

list

)

Starts the stream.

Parameters

list	[in] Optional list of input ResultSets

Returns

FALSE on error