4.3.80 ctdbFilterRecord

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Set the filtering logic for the table.

Declaration

CTDBRET ctdbFilterRecord(CTHANDLE Handle, pTEXT expr)

Description

ctdbFilterRecord sets the filtering for a table. When set, all records retrieved from the table are filtered against the expression and only records matching this criteria will be returned. This feature is temporary and the effect is limited to the user who sets the filter. The filter is turned off when the table is closed, or when ctdbFilterRecord is called with the record or table handle and NULL in the parameter expr. If a new expression is set to a table with a current filter, the old filter is replaced with the new one. Just one filter may be active per table per user.

When used in the client/server model, this feature has the potential to increase the performance since only records matching the criteria will be returned, reducing the network traffic.

ctdbGetFilter may be used to retrieve the filter and ctdbIsFilteredRecord to verify if there is a filter in the table.

Handle [in] the table or record handle.
expr [in] the filtering expression. The valid expressions are given in the table below.

Expression	Explanation
int atoi( char* String )	ASCII to integer.
int atol( char* String )	ASCII to long.
double atof( char* String )	ASCII to float.
int cabs( into Value )	Calculate the absolute value of a complex number.
int labs( into Value )	Calculate the absolute value of a long integer.
double fabs( double Value )	Calculate the absolute value of a float.
double ceil( double Value )	Calculate the ceiling of a value.
double floor( double Value )	Calculate the floor of a value.
double fmod( double r, double t )	Calculate the floating-point remainder.
int strlen( char* String )	Get the length of a string.
int strcmp( char* s, char* t )	Compare strings.
int stricmp( char* s, char* t )	Compare strings without regard to case.
int strncmp( char* s, char* t, int length )	Compare characters of two strings.
int strnicmp( char* s, char *t, int length )	Compare characters of two strings without regard to case.

If none of the above expressions is enough for the filtering logic the user would like to implement, there is yet a possibility of a user defined expression to be used. This so called "callback routine" is passed to the filter with an "at" sign (@) in the beginning of the expression. If this is done, what follows the @ is going to be the identifier to the user to handle in the routine ctfiltercb (located in ctclbk.c). Notice, though, that this is considered an advanced feature since it will require the editing of one of c-tree Plus source files to insert the call to the user defined routine(s).

Returns

ctdbFilterRecord returns CTDBRET_OK on success, or the c-tree Plus error code on failure.

See also

ctdbGetFilter, ctdbIsFilteredRecord, ctdbRecordSetOn