Tag：Database
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Time：2021-10-22
Four categories of NoSQL The position of NoSQL database in the whole database field is self-evident. In the era of big data, although RDBMS is excellent, RDBMS is gradually unable to cope with many database processing tasks in the face of the rapidly growing data scale and increasingly complex data model. At this time, NoSQL […]
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Time：2021-10-22
Series articles： Summer self-study day 09 | database (I) – SQL, DDL Summer self-study day 10 | database (II) – DML Summer self-study day 10 | database (III) – DQL Summer self-study day 11 | database (IV) – constraints Summer self-study day 12 | database (V) – multi table, database design Summer self-study day 13 […]
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Time：2021-10-22
1. Introduction Apollo (Apollo) is a production level configuration center product developed and open sourced by Ctrip framework department. It can centrally manage the configuration of applications in different environments and different clusters. After the configuration is modified, it can be pushed to the application end in real time. It also has standardized permissions, process […]
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Time：2021-10-22
PostgreSQL is a very powerful and open source client / server relational database management system (RDBMS). What is a database?Database is a warehouse that organizes, stores and manages data according to data structure.Each database has one or more different APIs for creating, accessing, managing, searching and copying saved data.We can also store data in files, […]
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Time：2021-10-22
1. Broken thoughts Recently, I encountered a problem in the business. The business is as follows: when inserting a new user, it is necessary to verify whether some information of the user is unique, and the verification result is always not unique in the program. Then I took out the SQL statement printed by mybatis […]
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Time：2021-10-22
introduce 1. What is a lock Lock is a mechanism by which a computer coordinates multiple processes or threads to access a resource concurrently. We call it lock mechanism 2. Why use the lock mechanism Because in the database, in addition to the contention of traditional computing resources (such as CPU, ram, I / O, […]
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Time：2021-10-22
In the series sharing of “domestic database hard core technology salon tdsql-a technology disclosure”, five Tencent cloud technology masters gave an in-depth interpretation of tdsql-a from the aspects of overall technical architecture, column storage and related execution optimization, cluster data interactive bus, distributed execution framework and vector execution engine. In the last issue of this […]
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Time：2021-10-22
Have you heard that Huawei cloud 11.11 cloud Carnival offers unprecedented discounts. Many enterprises rush to buy orders at that speed. It really doesn’t talk about martial ethics. Do it when you should. The activity is ready to end. If you haven’t rush to buy, you should hurry up, otherwise you really regret it!!! In […]
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Time：2021-10-22
Ora-12541: TNS: no listener Error when connecting to database:Error: ora-12541: TNS: no listener Interpretation:The listening service of the database is not started normally. Idea:1.Win+R——>services.msc——>CheckOracleOraDB12Home1TNSListener、OracleServiceORCLWhether the service is started. If not, click start and modify it to self start.2. If the problem still cannot be solved after startup, stop the above services first. Find the listening […]
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Time：2021-10-22
introduction In the first half of the year, I was responsible for a subject related to Python data analysis when I was working on my graduation project, and finally achieved a good result. I think the selection of technical scheme is of great value to share, and plays an introductory role in popularizing science for […]
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Time：2021-10-21
The front and rear ends are separated! When I first knew this, I was confused. Front end all go out to do spa, SEOs agree? Later, SSR came. He said, “the SEOs agreed!” Anyone’s opposition is useless. Times have changed. All kinds of spas have come, as well as all kinds of small programs wearing […]
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Time：2021-10-21
1、 Demand background First, let’s take a look at the requirements: the website counts the number of user logins, as follows: The website has 100 million users, including those who log in frequently and those who log in infrequently How to record user login information How to query active users: for example, log in three […]
