mongodb update 数组 操作

db.students.insert(       //插入测试数据
 [
 {"_id" :6, "grades" : [ 80, 85, 90 ],"score":[10,40,54]},
 {"_id" :7, "grades" : [ 88, 90, 92 ],"score":[100,30,51]}
 ]
);
//把满足score大于90的grades,数组的第一个元素设置成88
db.students.update(  { score: {$gt:90} },
            { $set: { "grades.$" : 88 } } ,
            { multi:true }
             );

$where = array("score"=>array('$gt'=>70));
$param = array('$set'=>array('grades.$'=>"303"));
$ismore = array("multiple" => true);
$collection->update($where,$param,$ismore);

db.test2.insert(
 {
 "content" : "this is a blog post.",
 "comments" :
 [
 {
 "author" : "Mike",
 "comment" : "I think that blah blah blah...",
 },
 {
 "author" : "John",
 "comment" : "I disagree."
 }
 ]
 }
);
//查找名为Mike的记录，并且该人的名字改成tank
db.test2.update( { "comments.author": "Mike"},
 { $set: { "comments.$.author" : "tank" } }
 );

$where = array("comments.author"=>"John");
$param = array('$set'=>array('comments.$.author'=>"tank"));
$ismore = array("multiple" => true);
$collection->update($where,$param,$ismore);

db.test3.insert(
 {"_id" :6, "grades" : [ "aaa", "bbb", "ccc" ]}
 );
db.test3.update( { _id: 6 }, { $addToSet: { grades: "ddd"  } });

$where = array("_id"=>6);
$param = array('$addToSet'=>array('grades'=>"eee"));
$collection->update($where,$param);

db.test3.update( { _id: 6 }, { $pop: { grades: -1 } }); //从头删除 
db.test3.update( { _id: 6 }, { $pop: { grades: 1 } }); //从尾删除

$where = array("_id"=>6);
$param = array('$pop'=>array('grades'=>-1));
$collection->update($where,$param);

> db.test3.find();
{ "_id" : 6, "grades" : [ "ccc", "ddd" ] }
{ "_id" : 7, "grades" : [ "aaa", "bbb", "ccc" ] }
{ "_id" : 8, "grades" : [ "aaa", "bbb", "ccc", "ddd", "eee" ] }
> db.test3.update(
 { grades: "aaa" },
 { $pull: { grades: "aaa" } }, //支持这种查找或匹配 $pull: { votes: { $gte: 6 } }
 { multi: true }
 );
WriteResult({ "nMatched" : 2, "nUpserted" : 0, "nModified" : 2 })

$where = array("grades"=>"bbb");
$param = array('$pull'=>array('grades'=>"bbb"));
$ismore = array("multiple" => true);
$collection->update($where,$param,$ismore);

db.students.update( { _id: {$gt:1} },
 { $pullAll: { "grades": [90,92] } } //只支持数组
 );

$where = array("grades"=>"ddd");
$param = array('$pullAll'=>array('grades'=>array("ddd","eee")));
$ismore = array("multiple" => true);
$collection->update($where,$param,$ismore);

db.test4.insert(
{
 "_id" : 5,
 "quizzes" : [
 { wk: 1, "score" : 10 },
 { wk: 2, "score" : 8 },
 { wk: 3, "score" : 5 },
 { wk: 4, "score" : 6 }
 ]
}
);
db.test4.update( { _id: 5 },
 { $push: { quizzes: { $each: [ { wk: 5, score: 8 },
                                { wk: 6, score: 7 },
                                { wk: 7, score: 6 } ],
                       $sort: { score: -1 },
                       $slice: 3,
                       $position:2
                      }
           }
 }
 );

$where = array("_id"=>5);
$param = array('$push'=>array('quizzes'=>array('$each'=>array(array("wk"=>9,"score"=>10),array("wk"=>20,"score"=>11)),
                                               '$sort'=>array("score"=>-1),
                                               '$position'=>2,
                                               '$slice'=>3        //用$slice一定要小心，在这里会把整表数据裁减成3条
                                              )
                                   )
                       );
$collection->update($where,$param);