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backgroundThe timing scenario of the Internet of things is one of the hottest directions at present. Massive time series data such as vehicle trajectory data, vehicle status monitoring data and sensor real-time monitoring data need to be stored in the database. In general, the following requirements exist in such scenariosData high write, low r ...

Tip: After the article is written, the catalog can be generated automatically, how to generate the help document to the right Article Directory PrefaceI. Database Operation StatementPreparedStatementResultSetResultSetMetaData2. Return a record in a table for different table query operationsthree And implement common query operatio ...

Java Web - Database Connection Pool and DBUtils Tools Database Connection Pool Definition In JDBC programming, each time a Connection object is created and disconnected, it takes time and IO resources. This is because when a Java program establishes a connection to a database, the database side verifies the user name and password, and to ...

4. DQL query data (the most important) 4.1 DQL (date query language: Data Query Language) All query operations use it, selectSimple queries and complex queries are availableThe core language and the most important statement in the databaseMost frequently used statements select[ALL | DISTINCT] { * | TABLE.* | [table.field1[as alias1][,table. ...

2. Operation database Operation database > operation database table > operation database table data 2.1 operation database (understand) 1. Create database create datebase name; 2. Delete database drop datebase name; 3. Use database -- tab Above the key,If your table name or field name is a special character, you need to bring ...

catalogue 1. Concepts of stored procedures and functions 2. Benefits of stored procedures and functions 3. Differences between stored procedures and functions 4. Create stored procedure 5. Call stored procedure 6. View stored procedures 7. Delete stored procedure 8. Stored procedure syntax 8.1 introduction to stored procedure syntax 8 ...

Crazy God video address https://www.bilibili.com/video/BV1S54y1R7SB 1,NoSQL 1.1 why use Nosql Have some chicken soup first We are now in 2020, in the era of big data;The general database of big data cannot be analyzed!Force yourself to study! Only continuous learning! This is the only law to survive in this society!Study or for yo ...

Preface JDBC is a set of interface s developed by SUN Company 1. Overview of JDBC 1. What is JDBC? Java DataBase Connectivity (Java Language Connectivity Database) 2. What is the nature of JDBC? JDBC is a set of interface s developed by SUN Company java.sql. *; (There are many interfaces under this package.) 3. Why Interface-orie ...

SQL multi table query #Alias table names SELECT st.class_num,cl.class_name FROM student st,class cl #Connection query Find out the class name of each student #The table on the left is the main table (the most used) SELECT st.class_num,cl.class_name FROM student st,class cl # the table on the right is the main table SELECT student.name,s ...

The most used go client of kafka should be sarama, but the old version of sarama did not support the consumption mode of consumer groups, so most people use sarama cluster.Later, sarama supported the consumption mode of consumer groups, and sarama cluster stopped maintenance. However, there are few online analysis of sarama consumer groups, and ...