CoreDX DDS C Reference Manual
Related Functions | List of all members
DDS_QueryCondition Struct Reference

A DDS_QueryCondition is a specialized DDS_ReadCondition which includes a filter. More...

Related Functions

(Note that these are not member functions.)

unsigned char DDS_QueryCondition_get_trigger_value (DDS_QueryCondition qc)
 This routine returns the current value of the trigger_value in qc. More...
 
DDS_DataReader DDS_QueryCondition_get_datareader (DDS_QueryCondition qc)
 This routine returns the single DDS_DataReader associated with this QueryCondition.
 
DDS_SampleStateKind DDS_QueryCondition_get_sample_state_mask (DDS_QueryCondition qc)
 This routine returns the current value of the sample_state in this QueryCondition.
 
DDS_ViewStateKind DDS_QueryCondition_get_view_state_mask (DDS_QueryCondition qc)
 This routine returns the current value of the view_state in this QueryCondition.
 
DDS_InstanceStateKind DDS_QueryCondition_get_instance_state_mask (DDS_QueryCondition qc)
 This routine returns the current value of the instance_state in this QueryCondition.
 
const char * DDS_QueryCondition_get_query_expression (DDS_QueryCondition qc)
 This routine returns the SQL query expression of this QueryCondition. More...
 
DDS_ReturnCode_t DDS_QueryCondition_get_query_parameters (DDS_QueryCondition qc, DDS_StringSeq *seq)
 This routine returns the parameters to the SQL query expression of this QueryCondition. More...
 
DDS_ReturnCode_t DDS_QueryCondition_set_query_parameters (DDS_QueryCondition qc, DDS_StringSeq *parameters)
 This routine sets the parameters to the SQL query expression of this QueryCondition. More...
 

Detailed Description

A DDS_QueryCondition is a specialized DDS_ReadCondition which includes a filter.

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

Not Yet Supported:
CoreDX DDS does not yet implement QueryConditions as a trigger for a WaitSet.

Friends And Related Function Documentation

const char * DDS_QueryCondition_get_query_expression ( DDS_QueryCondition  qc)
related

This routine returns the SQL query expression of this QueryCondition.

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

DDS_ReturnCode_t DDS_QueryCondition_get_query_parameters ( DDS_QueryCondition  qc,
DDS_StringSeq *  seq 
)
related

This routine returns the parameters to the SQL query expression of this QueryCondition.

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
DDS_DataReader_create_querycondition()
DDS_QueryCondition_set_query_parameters()
unsigned char DDS_QueryCondition_get_trigger_value ( DDS_QueryCondition  qc)
related

This routine returns the current value of the trigger_value in qc.

A non-zero return value indicates that the trigger_value is TRUE.

A zero return value indicates that the trigger_value is FALSE.

DDS_ReturnCode_t DDS_QueryCondition_set_query_parameters ( DDS_QueryCondition  qc,
DDS_StringSeq *  parameters 
)
related

This routine sets the parameters to the SQL query expression of this QueryCondition.

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
DDS_DataReader_create_querycondition()

© 2009-2017 Twin Oaks Computing, Inc
Castle Rock, CO 80108
All rights reserved.