Table of contents
1. Get to know Redis first
1.1. Understanding NoSQL
1.1.1. Structured and unstructured
1.1.2. Association and non-association
1.1.3. Query method
1.1.4. Transactions
1.1.5. Summary
1.2. Understanding Redis
1.3. Install Redis
1.3.1. Dependent library
1.3.2. Upload the installation package and decompress it
1.3.3. St ...
Article directoryBasic SELECT statementSELECT...SELECT ... FROMcolumn aliasremove duplicate rowsNull values ​​participate in operationsEmphasisQuery constants (add constant fields to queries at the same time)show table structurefilter datapractice questionsBasic SELECT statementSELECT...SELECT 1+1, 2+2;# Writing this directly is equivalent to t ...
Posted by jsinker on Thu, 02 Feb 2023 10:59:00 +0300
JDBC
overview
JDBC is independent of a specific database and is a common interface for accessing and operating common SQL statements
In addition to JDBC, there are also JDO, Hibernate, and Mybatis that can be used for general access to SQL statements, but they only better encapsulate JDBC. In the final analysis, JDBC is still used for databa ...
Posted by JoeZar on Thu, 02 Feb 2023 09:02:21 +0300
1. Generate random time
SELECT DATE_ADD('2021-01-01 00:00:00', INTERVAL FLOOR(1 + (RAND() * 10800)) SECOND )
Generate random numbers
SELECT UUID()
2. group by optimization
loose index Part of the scanned index needs to satisfy the left matching rule of the joint index. compact index Range index scan or full scan. There is a gap in ...
Posted by jmfillman on Thu, 19 Jan 2023 08:31:38 +0300
1. Select all employees in department 30;
Note: All employees are to be checked
scoped to sector 30
code show as below:
mysql> select * from emp where deptno = 30;
2. List the names, numbers and department numbers of all clerks (CLERK);
Note: What you want to check is name, serial number and department serial number
clerk
code sh ...
Posted by TylerL on Thu, 05 Jan 2023 18:21:51 +0300
Database Study Notes (2)1. Database Security1.1 TCSEC/TDI security level classificationB1 level: "secure" or "trusted" products, truly secure products1.2 Database management system security control modelAccess control process:The database management system authenticates the database users who make SQL access requests to prev ...
Posted by speedyslow on Mon, 02 Jan 2023 10:48:29 +0300
Node.js in action
Chapter 3 What is a Node Web Application
3.3 Add database
As far as adding a database to a Node program is concerned, there are no mandatory rules, but generally the following steps are involved.
Decide which database system you want to use.Check out popular modules on npm that implement database drivers or object-rela ...
Posted by garygay on Tue, 27 Dec 2022 03:38:58 +0300
# Redis overview installationApplication ScenarioCooperate with relational database for cacheVarious data structures store persistent dataRedis installationinstalled versioninstallation stepsBackground start (recommended)foreground startRedis introduces related knowledgeRedis is an open source key-value storage system.Similar to Memcached, it s ...
Posted by konrados on Sun, 25 Dec 2022 10:52:01 +0300
Foreword: This series is about learning .net related knowledge by myself in order to keep up with the pace of .net cross-platform. The current working reason is basically below .net Framework4.7, so I have this series of learning summary, but it is not from The basic C# syntax and basic knowledge started, but around the important design and dif ...
Posted by Bah! Name on Thu, 22 Dec 2022 17:23:01 +0300
Alibaba Cloud provides 5 ways to use oss storage, including console, command line, graphical management tool ossbrowser, SDK, and REST API; here are some descriptions of the commonly used command line and javasdk, and the others are not detailed one by one. Note, if you are interested, you can go to the official website to see related documents ...
Posted by newbie9999 on Wed, 14 Dec 2022 07:42:55 +0300