Mongodb中的js语法

1. 定义一个变量
2. > var len = 10;
3. For循环 这里的db和data都可以作为对象 save是方法 接收一个临时定义的对象
4. > for(var i = 0; i < len; i++){db.data.save({x:i})};
5. WriteResult({ "nInserted" : 1 })
6. > db.data.find();
7. { "_id" : ObjectId("593177646a6bb0f03293efe1"), "x" : 0 }
8. { "_id" : ObjectId("593177646a6bb0f03293efe2"), "x" : 1 }
9. { "_id" : ObjectId("593177646a6bb0f03293efe3"), "x" : 2 }
10. { "_id" : ObjectId("593177646a6bb0f03293efe4"), "x" : 3 }
11. { "_id" : ObjectId("593177646a6bb0f03293efe5"), "x" : 4 }
12. { "_id" : ObjectId("593177646a6bb0f03293efe6"), "x" : 5 }
13. { "_id" : ObjectId("593177646a6bb0f03293efe7"), "x" : 6 }
14. { "_id" : ObjectId("593177646a6bb0f03293efe8"), "x" : 7 }
15. { "_id" : ObjectId("593177646a6bb0f03293efe9"), "x" : 8 }
16. { "_id" : ObjectId("593177646a6bb0f03293efea"), "x" : 9 }
17. 使用游标查询
18. > var cur = db.data.find();
19. > cur[1]
20. { "_id" : ObjectId("593177646a6bb0f03293efe2"), "x" : 1 }
21. > printjson(cur[1])
22. { "_id" : ObjectId("593177646a6bb0f03293efe2"), "x" : 1 }
23. > var cur = db.data.find();
24. 对游标执行While循环
25. > while(cur.hasNext()) printjson(cur.next());
26. { "_id" : ObjectId("593177646a6bb0f03293efe1"), "x" : 0 }
27. { "_id" : ObjectId("593177646a6bb0f03293efe2"), "x" : 1 }
28. { "_id" : ObjectId("593177646a6bb0f03293efe3"), "x" : 2 }
29. { "_id" : ObjectId("593177646a6bb0f03293efe4"), "x" : 3 }
30. { "_id" : ObjectId("593177646a6bb0f03293efe5"), "x" : 4 }
31. { "_id" : ObjectId("593177646a6bb0f03293efe6"), "x" : 5 }
32. { "_id" : ObjectId("593177646a6bb0f03293efe7"), "x" : 6 }
33. { "_id" : ObjectId("593177646a6bb0f03293efe8"), "x" : 7 }
34. { "_id" : ObjectId("593177646a6bb0f03293efe9"), "x" : 8 }
35. { "_id" : ObjectId("593177646a6bb0f03293efea"), "x" : 9 }
36. 多么典型的js语法 直接接收一个方法
37. > db.data.find().forEach(printjson);
38. { "_id" : ObjectId("593177646a6bb0f03293efe1"), "x" : 0 }
39. { "_id" : ObjectId("593177646a6bb0f03293efe2"), "x" : 1 }
40. { "_id" : ObjectId("593177646a6bb0f03293efe3"), "x" : 2 }
41. { "_id" : ObjectId("593177646a6bb0f03293efe4"), "x" : 3 }
42. { "_id" : ObjectId("593177646a6bb0f03293efe5"), "x" : 4 }
43. { "_id" : ObjectId("593177646a6bb0f03293efe6"), "x" : 5 }
44. { "_id" : ObjectId("593177646a6bb0f03293efe7"), "x" : 6 }
45. { "_id" : ObjectId("593177646a6bb0f03293efe8"), "x" : 7 }
46. { "_id" : ObjectId("593177646a6bb0f03293efe9"), "x" : 8 }
47. { "_id" : ObjectId("593177646a6bb0f03293efea"), "x" : 9 }
48. 接收一个临时定义的带参数的方法
49. > db.data.find().forEach(function(e){printjson(e)});
50. { "_id" : ObjectId("593177646a6bb0f03293efe1"), "x" : 0 }
51. { "_id" : ObjectId("593177646a6bb0f03293efe2"), "x" : 1 }
52. { "_id" : ObjectId("593177646a6bb0f03293efe3"), "x" : 2 }
53. { "_id" : ObjectId("593177646a6bb0f03293efe4"), "x" : 3 }
54. { "_id" : ObjectId("593177646a6bb0f03293efe5"), "x" : 4 }
55. { "_id" : ObjectId("593177646a6bb0f03293efe6"), "x" : 5 }
56. { "_id" : ObjectId("593177646a6bb0f03293efe7"), "x" : 6 }
57. { "_id" : ObjectId("593177646a6bb0f03293efe8"), "x" : 7 }
58. { "_id" : ObjectId("593177646a6bb0f03293efe9"), "x" : 8 }
59. { "_id" : ObjectId("593177646a6bb0f03293efea"), "x" : 9 }