mongodb 3 4

directory MongoDB Study Notes (1) Introduction and installation of MongoDBMongoDB Study Notes (2) use the samus driver to perform basic data operationsMongoDB learning notes (3) using jqgrid tables to operate MongoDB data in MVC ModeMongoDB learning notes (4) describe the data relationship using the document structur

Problem description: there are now n ordered arrays in M groups, such as {1, 2, 3, 4}, {2, 3, 6}, {1, 3, 5, 7 }, select the data smaller than K in these arrays and return this value. Idea: Compare the minimum data selected each time by referring to the process of merging two Arrays 1. Define the selection position arra

\ data Directory D: \ mongodb \ data \ db database directory D: \ mongodb \ data \ log database log directory 2. decompress the latest mongodb package and copy the bin folder to the mongodb folder. 3100000000.exe is a shell client, and mongod is performed by the database itself. It can be run in the dos window. For

": "Wangwu", "Age" : $ > Db.stud Ent.find (). Skip (3). Limit (3) "_id": 4, "name": "Zhaoliu", "Age": "_id": 5, "name": " Qianliu "," Age ": " _id ": 6," name ":" Sunba "," Age ": + > Db.student.find (). SK IP (6). Limit (3) "_id": 7, "name": 7, "Age": 70} Db. Collection name. Find (). Sort ({key: number})A number of

helpful. The order of a single column index does not affect the query of the key immediately. Create a single column index: > db.people.ensureIndex({"name" : 1}) 3). Composite Index You can also create a composite index on multiple keys. The key position and index order affect the query efficiency. See the following: > db.people.ensureIndex({"name" : 1, "age" : 1})> db.people.ensureIndex({"age" : 1, "name" : 1}) In the first case, the Organization is

Lesson 4 MongoDB Data Query (1): mongodb Data Query1. Course outlineThis course mainly describes MongoDB Data Query related content, including the introduction and use of the find function, query operator introduction and use, embedded document query, and array query. 1. Introduction and use of the find function 2. int

Summary:Ordinary BST does not guarantee a good performance after multiple operations. So we need a BST, yes. The cost of each insertion and search is a logarithmic function of the large size of the tree. The 2-3-4 tree is a kind of BST that maintains balance.2-3-4 Tree IntroductionTo ensure that BST is balanced, we nee

Exercise 3-3 the last three bits of the productEnter several words, enter a number of integers (which can be positive, negative, or 0), and output the last three bits of their product. These integers are mixed with a string of uppercase letters, and your program should ignore them. Tip: Try to enter a string when executing scanf ("%d").#include Summary: 1 Note overflow2 for a break in the bad, the next code