Tag：Indexes
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Time：2020-10-30
In recent months, especially after the release of tidb RC1, more and more users have started to test it, and many friends have used it in the production environment. We have also received a lot of user’s test and use feedback. Thank you very much for the love of your friends and early users. After […]
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Time：2020-10-30
preface This article is mainly for developers, so it does not involve MySQL service deployment and other operations, and more content, we are ready to be patient and melon seed mineral water A while ago, I studied MySQL systematically and had some practical experience. I happened to see an interview article related to MySQL, and […]
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Time：2020-10-29
Collection of reasons for slow query speed of SQL Server There is no index or index is not used (this is the most common problem of slow query, which is a programming defect). The I / O throughput is small, forming a bottleneck effect. The computed column was not created, which caused the query not […]
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Time：2020-10-28
Database XX language: DDL, DML, DQL, DCL 1 database 1.1 connecting to the database Command line connection mysql -uroot -p update mysql.user Set password = password (‘xxx ‘) where user =’root’ and host =’localhost ‘; — modify user password Flush privileges; — refresh permissions ———————————————– show tables; Description Table Exit; — exits the connection 1.2 […]
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Time：2020-10-27
Introduction of database service concept Database: mainly used for effective analysis and processing of a large number of data informationDatabase server: MySQL maridbDatabase: storing data, classifying user information — user information base, commodity information — commodity transaction information — payment businessDatasheet: Datasheet informationData field: store specific content information, store information specificationData line: real every legal […]
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Time：2020-10-27
1、 Sequence Sequence is a special object in Oracle database, which can generate continuous integer values. It can be used by multiple objects in the database, and is mainly used as the primary key value.1. Create sequenceStart value with:1Increment by: 1Maximum value: maxvalue:100Minimum value: minvalue:1Cycle | nocycleBuffer: cache 20 | nocache (default: 20) create sequence s1;Note: […]
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Time：2020-10-27
In the past, readers often asked me where I could find the past and present life of go language. At this time, we often told him to read issues and proposals. But the data is a little scattered and there is no index system. As a result, many new beginners of the reader read on […]
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Time：2020-10-26
Data to loop $scope.friends = [ {name:’John’, age:25, gender:’boy’}, {name:’Jessie’, age:30, gender:’girl’}, {name:’Johanna’, age:28, gender:’girl’}, {name:’Joy’, age:15, gender:’girl’}, {name:’Mary’, age:28, gender:’girl’}, {name:’Peter’, age:95, gender:’boy’}, {name:’Sebastian’, age:50, gender:’boy’}, {name:’Erika’, age:27, gender:’girl’}, {name:’Patrick’, age:40, gender:’boy’}, {name:’Samantha’, age:60, gender:’girl’} ]; 1、 Definition and usage The ng repeat instruction is used to loop out HTML elements for a specified […]
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Time：2020-10-25
Leetcode question 1: the sum of two numbers Subject address https://leetcode-cn.com/probl… Title Description Given an integer array nums and a target value target, please find the two integers whose sum is the target value in the array and return their array subscripts. You can assume that there is only one answer for each input. However, […]
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Time：2020-10-25
This article was published by PostgreSQL Global Development Group on September 24, 2020 with the assistance of the translation volunteer group of China open source software promotion alliance PostgreSQL branch. PostgreSQL global development team today announced the official release of PostgreSQL 13, the latest version of the world’s most advanced open source database. PostgreSQL 13 […]
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Time：2020-10-25
Facing the vast amount of data on the Internet, how to quickly find the information you need? Search Engines! Enter the keywords, press enter, and mass results are waiting for you to review. But in the enterprise environment, facing a variety of IT systems, document libraries, and other kinds of different data sources, how to […]
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Time：2020-10-24
1 Introduction It is implemented by clean C. Need to be called by the host program, you can inject C functions. Grammar Convention Lua’s grammar is based on the grammatical rules of BNF. Lua is case sensitive. 2.1 reserved keywords The keywords not available in C language are: and elseif functionin nil local not orrepeat […]
