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Database introduction: Carrier for data storage in the operating system: Windows. Linux and macos are file based operating systems Database system: refers to a system that can provide information services for users. It achieves organized. The function of dynamically storing a large amount of relevant data provides a convenient means for data ...

Business scenario 1 Automatic dialogue of semantic recognition language in the field of artificial intelligence. The trial behavior of trial users is limited to 10 calls per minute Solution 1. Design a counter to record the call times, which is used to control the service execution times. Take the user id as the key and the usage times as th ...

Basic operation of MongoDB learningThe aggregation operation of mongo is similar to the query of mysqlSQL operations / functionsmongodb aggregation operationwhere$matchgroup by$grouphaving$matchselect$projectorder by$sortlimit$limitsum()$sumcount()$sumjoin$lookupThe following examples are compared with sqlThe following is a basic structure for ...

1, Basic command 1. Switch database (select) redis has 16 databases by default, and the 0 database is used by default Command for switching data: select number localhost:6379> select 2 OK # Switching succeeded localhost:6379[2]> # 6379 [2] represents the third database 2. set and get methods Command 1: set ...

​ ​ 1 Summary How does MongoDB implement aggregate queries? Group query? Group paging query? User defined time interval query? Time format conversion query? Don't panic. This article will introduce the implementation of grouping and aggregation query of various dimensions based on SpringBoot 2.X MongoTemplate, and catch all the complex qu ...

From my point of view, this article is a little rough. After all, it doesn't take much time. As an entry point, it may not enter the door? Redis is a very powerful database. I once read his source code and marveled at the monotony of his bottom layer, but the variability of his top layer. This is in response to the sentence "Tao gener ...

title: Redis6 Introduction (I) NoSQL database NoSQL database summary NoSQL(NoSQL = Not Only SQL), which means "not just SQL", generally refers to non relational databases. NoSQL does not rely on business logic storage, but is stored in a simple key value mode. Therefore, it greatly increases the expansion ability of the databa ...