QueryCondition Class Reference

Inheritance diagram for QueryCondition:

Public Member Functions
String	get_query_expression ()
ReturnCode_t	get_query_parameters (List< String > eparams)
ReturnCode_t	set_query_parameters (List< String > parameters)
Public Member Functions inherited from ReadCondition
uint	get_sample_state_mask ()
uint	get_view_state_mask ()
uint	get_instance_state_mask ()
DataReader	get_datareader ()
Public Member Functions inherited from Condition
bool	get_trigger_value ()

Detailed Description

The trigger_value is driven by the data available, after applying the filter, in the associated DataReader.

CoreDX DDS fully supports QueryConditions as an argument to DataReader::read_w_condition() and DataReader::take_w_conditions()

See also

DataReader::create_querycondition()

FooDataReader::read_w_condition()

FooDataReader::take_w_condition()

Not Yet Supported:

CoreDX DDS does not yet support QueryConditions as triggers for a WaitSet.

Member Function Documentation

String get_query_expression ( )

inline

Provides access to the query expression.

The query expression is an SQL syntax conditional expression that is provided when the QueryCondition is created.

See also

DataReader::create_querycondition()

ReturnCode_t get_query_parameters ( List< String >  eparams )

inline

Provides access to the parameters of the query expression.

The query expression is an SQL syntax conditional expression that is provided when the QueryCondition is created. The query expression may contain references to positional parameters of the form '%0', '%1'. These parameters can be changed dynamically to affect the expression.

See also

DataReader::create_querycondition()

QueryCondition::set_query_parameters()

ReturnCode_t set_query_parameters ( List< String >  parameters )

inline

Modifies the parameters of the query expression.

The query_expression is an SQL like condition expression, and the parameters argument provides optional parameters that are referenced by the query_expression. The syntax for refering to paramters in a query_expression is the percent sign '' followed by a number. The number is the index of the paramter in the query_paramters sequence. Parameters are counted starting at zero. So, "%0" refers to the first parameter, and "%4" refers to the fifth paramter. Using this syntax, the expression "x<%0" would test the value of 'x' against the first parameter in the sequence.

This routine allows the parameters to be changed dynamically.

See also

DataReader::create_querycondition()