This function is EXPERIMENTAL. The behaviour of this function, the name of this function, and anything else documented about this function may change without notice in a future release of PHP. Use this function at your own risk.
Constraints are triplets of strings containing of a domain name, a comparison operator and a comparison value. The constraints parameter array may consist of a collection of string arrays, each of which contains a domain, an operator and a value, or of a single string array containing a multiple of three elements.
The comparison operator may be one of the following strings: '==', '>', '>=', '<', '<=', '!=', '~' for a regular expression match and 'BAND' or 'BOR' for bitwise operations.
See also dbplus_unselect().