ToC path:

mco_uda_register_collation

Register a collation.

Prototype

 
    MCO_RET mco_uda_register_collation(	/*IN*/ const mco_metadict_header_t * metadict, 
                        /*IN*/ unsigned short dict_no,
                        /*IN*/ unsigned short collation_no, 
                        /*IN-OUT*/ mco_collation_funcs_h coll_map,
                        /*IN*/ mco_compare_collation_f fcomp,
                        /*IN*/ mco_hash_collation_f fhash );

Arguments

metadict	The address of an initialized mco_metadict_header_t structure
dict_no	The number of the dictionary (must be between 0 and `mco_metadict_count()` - 1)
collation_no	The collation number
coll_map	The address of an `mco_collation_funcs_h` collation functions structure. This will be initialized to point to the compare and hash functions when the collation is successfully registered
fcomp	The application-supplied collation compare function. (See mco_compare_collation_f defined in mco.h)
fhash	The application-supplied collation hash function. (See mco_hash_collation_f defined in mco.h)

Description

Register a collation with the database runtime.

Return Codes

MCO_S_OK	Collation registered successfully
MCO_E_UDA_COLLATION_NOTFOUND	Collation not found
MCO_ERR_UDA	Fatal error registering collation

Example

 
    Application snippet:
        
     
    /* custom compare & hash functions */
    int2 coll_cmp(mco_collate_h c1, uint2 len1, mco_collate_h c2, uint2 len2)
    {
        mco_uda_value_t val1, val2;
        char buf1[20], buf2[20];
         
        /* get first object's value */
        val1.type = MCO_DD_STRING;
        val1.v.p.size = sizeof(buf1);
        val1.v.p.p.c = buf1;
        mco_uda_collate_get(c1, &val1);
         
        /* get second object's value */
        val2.type = MCO_DD_STRING;
        val2.v.p.size = sizeof(buf2);
        val2.v.p.p.c = buf2;
        mco_uda_collate_get(c2, &val2);
         
        /* compare values */
        return STR_CMP(buf1, buf2);
    }
     
    uint4 coll_hash(mco_collate_h c, uint2 len)
    {
        mco_uda_value_t val;
        char buf[20];
         
        /* get object's value */
        val.type = MCO_DD_STRING;
        val.v.p.size = sizeof(buf);
        val.v.p.p.c = buf;
        mco_uda_collate_get(c, &val);
         
        /* hash value */
        return strlen(buf);
    }
     
    int main(int argc, char *argv[])
    {
        MCO_RET rc;
        mco_collation_funcs_h coll_map;
        unsigned int coll_map_size; 
        mco_metadict_header_t *metadict;
         
         
        …
         
        /* allocate collmap */
        mco_uda_get_collmap_size(metadict, 0, &coll_map_size);
        coll_map = (mco_collation_funcs_h) malloc(coll_map_size);
         
        /* register collation compare & hash functions */
        rc = mco_uda_register_collation(metadict, 0, coll_no, coll_map, &coll_cmp, &coll_hash);
        
        …
    }

Files

Header file:

mcouda.h

Source file:

mcouda.c

Library:

libmcouda.a