本文是对mongodb学习的一点笔记,主要介绍最简单的增删改操作,初学,看着API,有什么错误,希望大家指正:(使用官方驱动) 1.增 增加操作是最简单的,构造bsonDcument插入即可: 方式1,直接构造: MongoServer dbserver = new MongoClient(connectionStr)
本文是对mongodb学习的一点笔记,主要介绍最简单的增删改操作,初学,看着API,有什么错误,希望大家指正:(使用官方驱动)
1.增
增加操作是最简单的,构造bsonDcument插入即可:
方式1,直接构造:
MongoServer dbserver = new MongoClient(connectionStr).GetServer(); MongoDatabase db = dbserver.GetDatabase(dbName); MongoCollection collection = db.GetCollection(collectionName); dbserver.Connect(); BsonDocument doc = new BsonDocument(); doc["Age"] = Int32.Parse(txt_Age.Text); doc["Name"] = txt_Name.Text; doc["Num"] = txt_Num.Text; doc["Introduction"] = txt_Introduction.Text; collection.Insert(doc);
方式2,通过实体构造:
1 var student = new Student 2 { 3 Age = Int32.Parse(txt_Age.Text), 4 Name = txt_Name.Text, 5 Num = txt_Num.Text, 6 Introduction = txt_Introduction.Text 7 }; 8 9 collection.Insert(student);
2.删
关键就是构造删除条件,通过api查到Remove方法的签名:public virtual WriteConcernResult Remove(IMongoQuery query);在网上看到好多写法都是在Remove中传入BsonDocument对象,但是我查源码发现bsonDocument根本没有实现IMongoQuery接口,实现这个接口的是一个叫做QueryDocument的类,同时QueryDocument也继承了BsonDocument对象,而构造BsonDocument和QueryDocument的方式超级多,各种方便,简单写几种:
比如构造如下条件,delete from table where?Age>15 &Age
相应的mongodb条件写法:{Age:{$gt:15,$lt:20}},下面就来构造这个条件;
方式1,直接通过bsonDocument构造:
BsonDocument doc = new BsonDocument { { "Age",new BsonDocument{{"$gte",10},{"$lte",15}}} };
方式2,直接通过QueryDocument构造:与1类似
1 QueryDocument query = new QueryDocument 2 { 3 { "Age",new QueryDocument{{"$gte",10},{"$lte",15}}} 4 };
方式3,直接通过反序列化json字符串:
1 string json = "{ Age:{$gte:10,$lte:15}}"; 2 var queryJson = BsonSerializer.Deserialize(json, typeof(BsonDocument)) as BsonDocument;
个人觉得这种方式挺好,如果你mongodb命令熟悉,这种方式挺适合构造复杂条件的
方式4:通过Query类,Query是静态类,封装了各种逻辑条件方法,有泛型和泛型两种方式:
1 var query1 = Query.GT("Age", 10);//大于10;greater than 10 2 var query2 = Query.LT("Age", 15);//小于15;less than 15 3 var query = Query.And(query1, query2);
但是更好的要数泛型方式了:
var query1 = Query.GTE(t => t.Age, 10); var query2 = Query.LTE(t => t.Age, 15); //var query = Query.And(Query.GTE("Age", 10), Query.LTE("Age", 15)); var query = Query.And(query1, query2);
最后执行Remove方法即可;
3.查
数据显示是必不可少的,查询操作中的条件过滤在删除中已说过,不再赘述,这里先写两种方式(ps:现在了解太浅,只能以笔记形式记录下)
方式1:通过FindAllAs方式或者FindAs方法
1 var query1 = Query.GTE(t => t.Age, 10); 2 var query2 = Query.LTE(t => t.Age, 15); 3 var query = Query.And(query1, query2); 4 5 var list = collection.FindAs(typeof(Student), query);
方式2:通过linq
1 var qList = (from c in collection.AsQueryable() 2 where c.Age > 10 && c.Age <p class="copyright"> 原文地址:MongoDB的增删改查, 感谢原作者分享。 </p>

InnoDBBufferPool reduces disk I/O by caching data and indexing pages, improving database performance. Its working principle includes: 1. Data reading: Read data from BufferPool; 2. Data writing: After modifying the data, write to BufferPool and refresh it to disk regularly; 3. Cache management: Use the LRU algorithm to manage cache pages; 4. Reading mechanism: Load adjacent data pages in advance. By sizing the BufferPool and using multiple instances, database performance can be optimized.

Compared with other programming languages, MySQL is mainly used to store and manage data, while other languages such as Python, Java, and C are used for logical processing and application development. MySQL is known for its high performance, scalability and cross-platform support, suitable for data management needs, while other languages have advantages in their respective fields such as data analytics, enterprise applications, and system programming.

MySQL is worth learning because it is a powerful open source database management system suitable for data storage, management and analysis. 1) MySQL is a relational database that uses SQL to operate data and is suitable for structured data management. 2) The SQL language is the key to interacting with MySQL and supports CRUD operations. 3) The working principle of MySQL includes client/server architecture, storage engine and query optimizer. 4) Basic usage includes creating databases and tables, and advanced usage involves joining tables using JOIN. 5) Common errors include syntax errors and permission issues, and debugging skills include checking syntax and using EXPLAIN commands. 6) Performance optimization involves the use of indexes, optimization of SQL statements and regular maintenance of databases.

MySQL is suitable for beginners to learn database skills. 1. Install MySQL server and client tools. 2. Understand basic SQL queries, such as SELECT. 3. Master data operations: create tables, insert, update, and delete data. 4. Learn advanced skills: subquery and window functions. 5. Debugging and optimization: Check syntax, use indexes, avoid SELECT*, and use LIMIT.

MySQL efficiently manages structured data through table structure and SQL query, and implements inter-table relationships through foreign keys. 1. Define the data format and type when creating a table. 2. Use foreign keys to establish relationships between tables. 3. Improve performance through indexing and query optimization. 4. Regularly backup and monitor databases to ensure data security and performance optimization.

MySQL is an open source relational database management system that is widely used in Web development. Its key features include: 1. Supports multiple storage engines, such as InnoDB and MyISAM, suitable for different scenarios; 2. Provides master-slave replication functions to facilitate load balancing and data backup; 3. Improve query efficiency through query optimization and index use.

SQL is used to interact with MySQL database to realize data addition, deletion, modification, inspection and database design. 1) SQL performs data operations through SELECT, INSERT, UPDATE, DELETE statements; 2) Use CREATE, ALTER, DROP statements for database design and management; 3) Complex queries and data analysis are implemented through SQL to improve business decision-making efficiency.

The basic operations of MySQL include creating databases, tables, and using SQL to perform CRUD operations on data. 1. Create a database: CREATEDATABASEmy_first_db; 2. Create a table: CREATETABLEbooks(idINTAUTO_INCREMENTPRIMARYKEY, titleVARCHAR(100)NOTNULL, authorVARCHAR(100)NOTNULL, published_yearINT); 3. Insert data: INSERTINTObooks(title, author, published_year)VA


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