ActiveJDBC – as ORM : ActiveJDBC logging & Primary Key

• ActiveJDBC logging & Primary Key

ActiveJDBC logging configuration

• ActiveJDBC uses SLF4J logging facade.
• ActiveJDBC uses a system property activejdbc.log for specifying logging. The value of this property can be:
• blank – in this case, ActiveJDBC will spit out all available information – every SQL statement, cache hits/misses, cache purge events, etc.
• regular expression – in this case, ActiveJDBC will only log statements that match a regular expression

Example

If you just want to see all messages from ActiveJDBC, start your program like this.

java -Dactivejdbc.log   com.javaskool.YourProgram

-If you only want to see select messages, you can provide an expression

java -Dactivejdbc.log=select.* com.javaskool.YourProgram

Primary Key

• ActiveJDBC, like ActiveRecord relies on the surrogate primary keys. A surrogate key is not generated by ActiveJDBC. Unlike Hibernate, it does not (currently)
  have any generators for the keys and relies fully on DBMS solution to do this.
• By convention, the primary key name is id. If your table has a surrogate primary key column with a name id, you do not have to do anything.

Override primary key

• If your table cannot provide a primary key column named id (for instance due to corporate naming standards), you can override it with @IdName annotation.
• Example: let’s say you have a table Flight

CREATE TABLE Flight( 
  flight_id int(11) NOT NULL AUTO_INCREMENT, 
  Src             VARCHAR(124), 
  Dest         VARCHAR(124), 
) 

You will then put annotation on the model

@IdName("flight_id") 
public class Flight extends Model{}

Composite Primary Keys

• Like ActiveRecord, ActiveJDBC does not support composite primary keys.
• However, this does not mean that you cannot use AJ on tables with declared composite PKs.
• All it means is that AJ does not provide any constraint checks, and relies on the DB for that.