//添加数据

db.users.insert({"uName":"张三","age":,"gender":"男"});

db.users.insert({"name":"李四","wifes":[{"wname":"小崔"},{"wname":"小李"}]});

//查询数据

db.students.find();

//查询数据（带格式显示）

db.users.find().pretty();

//分页查询

db.books.insert({"bookName":"mybatis入门","price":19.9});

db.books.insert({"bookName":"spring","price":199.9});

db.books.insert({"bookName":"springmvc","price":69.9});

db.books.insert({"bookName":"mysql","price":39.9});

db.books.insert({"bookName":"python","price":59.9});

// skip(起始页码，从0开始) limit(每页显示数量)

db.books.find().skip().limit();

db.books.find().skip().limit();

//条件查询

//select * from books where price = 19.9

db.books.find({"price":19.9});

// price = ? and bookName = ?

db.books.find({"price":19.9,"bookName":"mybatis入门"});

//or

db.books.find({$or:[{"bookName":"mybatis入门"},{"bookName":"spring"},{"price":59.9}]});

// <

db.books.find({"price":{$lt:69.9}})

// <=

db.books.find({"price":{$lte:69.9}});

// >

db.books.find({"price":{$gt:69.9}});

// >=

db.books.find({"price":{$gte:69.9}});

// !=

db.books.find({"price":{$ne:69.9}});

// >=39.9 and <=69.9

db.books.find({"price":{$gte:39.9,$lte:69.9}});

//修改

//udpate book set price = ? where bookName = ?

db.books.update({"bookName":"mybatis入门"},{$set:{"price":119.99}});

//若根据修改条件 需要修改多条数据时，需要添加参数 multi:true

db.books.update({"bookName":"mybatis入门"},{$set:{"price":1.99}},{multi:true});

//删除

//delete book where bookName = ?

db.books.remove({"bookName":"spring"});