如果存在一行，则返回ID，否则返回INSERT

我建议在数据库端进行检查，然后将ID返回给nodejs。

例子：

CREATE OR REPLACe FUNCTION foo(p_param1 tableFoo.attr1%TYPE, p_param2 tableFoo.attr1%TYPE) RETURNS tableFoo.id%TYPE AS $$  DECLARE  v_id tableFoo.pk%TYPE;  BEGIN    SELECT id    INTO v_id    FROM tableFoo    WHERe attr1 = p_param1    AND attr2 = p_param2;    IF v_id IS NULL THEN      INSERT INTO tableFoo(id, attr1, attr2) VALUES (DEFAULT, p_param1, p_param2)      RETURNING id INTO v_id;    END IF;    RETURN v_id:  END;$$ LANGUAGE plpgsql;

而不是在Node.js端（在此示例中，我使用的是node-postgres）：

var pg = require('pg');pg.connect('someConnectionString', function(connErr, client){  //do some errorchecking here  client.query('SELECt id FROM foo(, );', ['foo', 'bar'], function(queryErr, result){    //errorchecking    var id = result.rows[0].id;  };});