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MySQL 5.7 provides a new field format json, which is probably because MySQL wants to eat all non relational and relational databases, so it has introduced this very easy-to-use format. In this way, many of our businesses based on mongoDb or clickHouse can be implemented with MySQL. Of course, version 5.7 is only the most basic version, and the ...

MySQL complex query 1. Index MySQL Index building for MySQL The efficient operation of is very important, and the index can be greatly improved MySQL Search speed. Take the table of contents page (index) of a Chinese dictionary for example. We can quickly find the required words according to the table of contents (index) sorted by pinyin, s ...

Experiment 4 Java Web Programming 1, Experimental purpose 1. Master the installation and configuration of Tomcat, a Java Web server. 2. Learn simple HTML form design and form submission. 3. Master the use of request object and session object in JSP. 2, Experimental content 1. Download and install Tomcat8 and configure it. Start the Tomcat ...

Incremental synchronization of canal data from Mysql8.0 to ElasticSearch7 (windows local environment) As of the current date 2021-10-29 The current version of canal has only been updated to 1.1.6 This version of canal is going to use v1.1.5, which supports mysql8.0 and elasticsearch7. X If you use mysql5. X, elasticsearch6. X, v1.1.4 is ...

introduction Regular expressions are special strings used to match text (character set). If you want to extract a phone number from a text file, you can use a regular expression. If you need to find all files with numbers in the middle of the name, you can use a regular expression. If you want to find all duplicate words in a text block, ...

Query analysis and tuning backgroundIn the process of using the database, we often encounter the sudden slow down of SQL due to the following problems:Select wrong indexSelect the wrong connection orderRange queries use different quick optimization strategiesExecution method change of sub query selectionChange of policy mode of semi connection ...

catalogue 1, View 1. View definition 2. View creation, query, modification and Application 2, Null and null values 3, Application of regular expression in mysql 4, Operator 1. Arithmetic operator 2. Comparison operator 3. Logical operator (Boolean) 4. Bitwise operator 5. Operator priority summary 1, View 1. View definition &nb ...

catalogue preface 1, Index and classification 1. Concept of index 2. Function of index 3. Side effects of index 4. Classification of index 4.1 General Index 4.2 unique index 4.3 primary key index 4.4 full text index 4.5 combined index (single column index and multi column index) 5. Principles and basis of index creation 2, Create ...

When the client connects to the MySQL server, it must provide valid identity authentication, such as user name and password. When the user performs any database operation, the server will verify whether the user has corresponding permissions. For example, SELECT permission is required for query tables and DROP permission is required for deletin ...

introduction Database transaction refers to a series of operations performed as a single logical unit of work, either complete or not at all. Under normal circumstances, these operations will proceed smoothly and finally succeed. However, if there is a problem in any link in this series of processes, all information in the database must ...