// score 字段加 1
db('article')->where('id', 1)->setInc('score');
// score 字段加 5
db('article')->where('id', 1)->setInc('score', 5);
// score 字段减 1
db('article')->where('id', 1)->setDec('score');
// score 字段减 5
db('article')->where('id', 1)->setDec('score', 5);