In memory database

[ythy]

What is an in memory database?

Typical databases involve a lot of setup.

• Install the Database
• Setup a Schema
• Setup the tables
• Populate the data
• Connect the application to the database by setting up a data source and a lot of other code

Scenario 1 - Let’s consider a situation where you would want to do a quick DEV. Using a traditional database involves a lot of overhead.

Scenario 2 - Consider your unit tests You don’t want them to fail when some data/schema in the database changes You would want to be able to run them in parallel - multiple developers might be running the tests in parallel.

In these kind of scenarios, an in memory database provides an ideal solution. An in memory database is created when an application starts up and destroyed when the application is stopped.

Advantages

• Zero project setup or infrastructure
• Zero Configuration
• Zero Maintainance
• Easy to use for Learning, POCs and Unit Tests
• Spring Boot provides Simple Configuration to switch between a real database and an in memory database like H2

H2

H2 is one of the popular in memory databases. Spring Boot has very good integration for H2.

H2 is a relational database management system written in Java. It can be embedded in Java applications or run in the client-server mode.

H2 supports a sub set of the SQL standard. H2 also provides a web console to maintain the database.

[ythy]

必要的h2配置

# Enabling H2 Console
spring.h2.console.enabled=true

spring.datasource.url=jdbc:h2:mem:springs
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=

dependencies {
    compile('org.springframework.boot:spring-boot-starter-data-jpa')
    runtime('com.h2database:h2')
}

[ythy]

H2数据库控制台地址： 注意 JDBC URL 填spring.datasource.url 的值 http://127.0.0.1:7777/h2-console/

[ythy]

Important: 1.jdbc:h2:mem is used to define In-memory databases.

2. jdbc:h2:file is used to define disk-based databases.