//添加数据
db.users.insert({"uName":"张三","age":30,"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(0).limit(2);
db.books.find().skip(4).limit(2);
//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"});
