JDBC, MyBatis, log4j, Transaction과 오라클의 관계

 

1. The Java Database Connectivity (JDBC)

The Java Database Connectivity (JDBC) API is the industry standard for database-independent connectivity between the Java programming language and a wide range of databases – SQL databases and other tabular data sources, such as spreadsheets or flat files. The JDBC API provides a call-level API for SQL-based database access.

JDBC technology allows you to use the Java programming language to exploit "Write Once, Run Anywhere" capabilities for applications that require access to enterprise data. With a JDBC technology-enabled driver, you can connect all corporate data even in a heterogeneous environment.

 

JDBC는 자바에서 데이터베이스에 접속할 수 있도록 하는 자바 API이다. 

JDBC는 데이터베이스에서 자료를 쿼리하거나 업데이트하는 방법을 제공한다

 

2. MyBatis

MyBatis is a first class persistence framework with support for custom SQL, stored procedures and advanced mappings. MyBatis eliminates almost all of the JDBC code and manual setting of parameters and retrieval of results. MyBatis can use simple XML or Annotations for configuration and map primitives, Map interfaces and Java POJOs (Plain Old Java Objects) to database records.

 

마이바티스는 개발자가 지정한 SQL, 저장프로시저 그리고 몇가지 고급 매핑을 지원하는 퍼시스턴스 프레임워크이다. 마이바티스는 JDBC로 처리하는 상당부분의 코드와 파라미터 설정및 결과 매핑을 대신해준다. 마이바티스는 데이터베이스 레코드에 원시타입과 Map 인터페이스 그리고 자바 POJO 를 설정해서 매핑하기 위해 XML과 애노테이션을 사용할 수 있다.

 

3. log4j

log4j는 프로그램을 작성하는 도중에 로그를 남기기 위해 사용되는 자바 기반 로깅 유틸리티이다. 디버그용 도구로 주로 사용한다.

 

4. Transaction

A transaction is a logical, atomic unit of work that contains one or more SQL statements. A transaction groups SQL statements so that they are either all committed, which means they are applied to the database, or all rolled back, which means they are undone from the database. Oracle Database assigns every transaction a unique identifier called a transaction ID.

All Oracle transactions obey the basic properties of a database transaction, known as ACID properties. ACID is an acronym for the following:

• Atomicity
• All tasks of a transaction are performed or none of them are. There are no partial transactions. For example, if a transaction starts updating 100 rows, but the system fails after 20 updates, then the database rolls back the changes to these 20 rows.
• Consistency
• The transaction takes the database from one consistent state to another consistent state. For example, in a banking transaction that debits a savings account and credits a checking account, a failure must not cause the database to credit only one account, which would lead to inconsistent data.
• Isolation
• The effect of a transaction is not visible to other transactions until the transaction is committed. For example, one user updating the hr.employees table does not see the uncommitted changes to employees made concurrently by another user. Thus, it appears to users as if transactions are executing serially.
• Durability
• Changes made by committed transactions are permanent. After a transaction completes, the database ensures through its recovery mechanisms that changes from the transaction are not lost.

The use of transactions is one of the most important ways that a database management system differs from a file system.