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This article is reproduced in [ http://blog.csdn.net/liaohaojian/article/details/68488150] 1. The definition of a transaction: A transaction is a collection of multiple units of operation that are either not successful or successful.It must follow four principles (ACID). Atomicity: A transaction is the smallest unit of work that cannot be sep ...

In this article, we continue to look at other configuration elements. Today's protagonist is our <environments> element, which is used to set up the database configuration we need to access. Let's first look at the configuration: <environments default="development"> <environment id="development"> <!-- Use jdbc transa ...

Java 7 enhanced try statement closes resources Traditional ways of closing resources import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; class Student implements Serializable { private String name; public Student(String name) { this.name = name; ...

1. Introduction to OLAP 1. ConceptsOLAP is the abbreviation for On-Line Analytical Processing in English, meaning Online Analytical Processing.This concept was first proposed by E.F.Codd, the father of relational databases, in 1993.OLAP allows access to aggregated and organized data from business data sources in a structure called cubes.On-Line ...

1. JNDI: JNDI is ( Java Naming and Directory Inteface)Java Name directory interface. The role of JNDI is to bring resources into the server.You can think of JNDI as a repository.Put Java objects into JNDI. 2. Origin of data sources: In java development, use JDBC operations data base Several steps: 1. Use Class.forName (full pat ...

A Summary 1. What is dynamic query? Random selection of several query conditions from a number of combinations into a DQL statement for query, this process is called dynamic query. 2. Difficulties of Dynamic Query There are many optional query conditions and combinations, so it is difficult to list them one by one. 3. Composition of Fina ...

1 What is spring JDBC Spring simplifies the workload of JDBC programming by abstracting JDBC access and consistent APIs. We just need to declare the SQL, call the appropriate Spring JDBC framework API, and process the result set. Transactions are managed by Spring and JDBC checked exceptions are converted to Spring consistent unchecked exceptio ...

Spring's java configuration 1. Spring's java configuration Java configuration is recommended by Spring 4. X and can completely replace xml configuration. 1.1 Use @Configuration and @Bean Spring's Java configuration is implemented through @Configuration and @Bean annotations: 1. @Configuration acts on classes, which is equivalent to an xml confi ...

Use and Operation of Database Connection Pool (DBCP) When using SQL statements to operate databases in java, it is often necessary to load the driver first, establish a connection, and then execute some SQL after successful connection. After executing SQL, it is necessary to consider whether to close the connection. When there is another SQL ...

spring data jpa A subproject of Spring. Used to simplify database access, support NoSQL and relational data storage. Its main goal is to make database access convenient and fast. Dedicated to reducing the amount of data access layer (DAO) development. The only thing developers need to do is declare the persistence layer interface, and the re ...