Data source & Transaction

What is a datasource

The component that manages database connections. Usually it creates a connection pool, and serves connections to the server.

How to initialize sql schema and init data in spring boot

Create schema.sql and data.sql files inside resources.

What is JDBC template

Convenient abstraction over JDBC. More convenient than working with Stamtements and PreparedStatements, but it still uses Native sql queries.

JDBC template methods and what is RowMapper

methods:

• update() - uses it for insert, update, delete SQL commands

• query() - select

rowmapper is used with select - maps the resultset to the result objects.

How to use datasource with spring boot

1. add dependencies: jdbc, driver

2. create config in config file: url, username, password

3. Create optional HikariCP datasource bean.

What is a transaction?

Groups commands together and ensures that they all execute or none of them do.

How to make a transaction in spring boot, and how does it work?

• annotate method with @Transactional

• rollback happens on thrown RuntimeException → if you catch it, it won’t roll back!! U can customize this for Exception class