[CRM learning and development Day1 of SSM framework project customer relationship management system]

1.1 home page function demand When users visit the project home page, they first enter the login page. Timing & flow IndexController @Controller public class IndexController { /* Theoretically, assign a url to the Controller method: http://127.0.0.1:8080/crm/ For simplicity, the protocol: / / ip:port / application ...

Posted by goldfiles on Wed, 25 May 2022 00:07:31 +0300

Filters, listeners and mysql

review EL Syntax ${expression} EL domain objects, and lookup rules pageScope requestScope sessionScope applicationScope What is the function of pageContext object in EL You can get other objects ${ pageContext.request.contextPath } How does EL display the attributes of students, elements in list and elements in map ${Student object. Pro ...

Posted by konqest on Mon, 23 May 2022 01:54:54 +0300

centos7 quick guide for building MySQL NDB Cluster 7.5/7.6 cluster

NDB Cluster is a technology that enables in memory database clustering in a shareless system. Shareless architecture enables the system to use very cheap hardware with minimal specific requirements for hardware or software. NDB Cluster is designed without any single point of failure. In a non shared system, each component should have its own m ...

Posted by DrTom on Sun, 22 May 2022 08:32:09 +0300

Java topic Database connection pool, manually create connection pool+dbcp+C3P0+Druid+dbUtil

connection pool (database connection pool) Closing the link every time you link to the database is rather cumbersome and wastes time and resources. Now we can get the database link through the connection pool, and put it back after use up, which can save the time and operation of constantly creating and closing the connection, which is more eff ...

Posted by beckjo1 on Sun, 22 May 2022 06:26:33 +0300

Redis intersection union difference set

introduce Intersection: an element that appears at least twice in all setsUnion: combine the elements of multiple sets and remove the duplicate elementsDifference set: an element that exists in the first set and does not exist in other sets Related commands commandexplainsinter key [key ...]Gets the intersection of all setssinterstore desiti ...

Posted by KoopaTroopa on Sun, 22 May 2022 02:45:39 +0300

Redis data type (hash type)

hash type and operation ① Overview The hash type in Redis can be understood as a map container with String Key and String Value, so the hash type is suitable for storing value object information. Such as Username, Password or Age. Even if there are only a few fields in the hash, its data only takes up a small amount of disk space. Each ha ...

Posted by daniel_grant on Sat, 21 May 2022 04:01:06 +0300

Detailed process of Dameng mpp + active and standby

1. Refer to DM for software installation steps_ dw. txt First node Second node EP01 (main) EP02 ((main) EP12 (prepare) EP11 ((standby) 2. Install mpp active / standby --------------------First node 0.101 (1) Initialize instance EP01 main library: ./dminit PATH=/dm8/dmdata DB_NAME=EP01 INSTANCE_NAME="EP01" PORT_NU ...

Posted by shane07 on Sat, 21 May 2022 02:25:45 +0300

Mysql database 2: DML operation, multi table relationship and query operation

catalogue  1. DML - modify operation 2. DML delete 3. Mysql simple query operation 4. Multi table relationship and table building principle 4. Mysql multi table Association query 4.1 mysql Association query classification 4.2 write sql statement to realize mysql multi table Association query 5. Mysql query operation  1. DM ...

Posted by drag0n on Fri, 20 May 2022 23:14:59 +0300

How does FlinkX read and write to the Clickhouse?

Introduction: This paper will mainly introduce the process and related parameters of reading and writing Clickhouse by FlinkX. The core content will focus on the following three questions: 1 Which version does FlinkX Clickhouse support 2. What are the parameters for Clickhouse to read and write Clickhouse 3. What are the instructions for Clickh ...

Posted by pedroz on Fri, 20 May 2022 16:16:32 +0300

When deleting records logically - ensure the uniqueness of the business

catalogue Business background Business background Generally, some record tables of the business system have some uniqueness constraints. For example, duplicate names are not allowed under the same user; You can usually create a unique index on the specified column, for example: CREATE TABLE `novel` ( `id` bigint(20 ...

Posted by JayBachatero on Fri, 20 May 2022 14:36:13 +0300