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Can OJB handle ternary (or higher) associations?

April 26, 2017Associations ojb ternary

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Can OJB handle ternary (or higher) associations?

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Yes, that’s possible. Here is an example. With a ternary relationship there are three (or more) entities ‘related’ to each other. An example would be Developer , Language and Project . Each entity is mapped to one table (DEVELOPER , LANGUAGE and PROJECT ). To represent the combinations of these entities we need an additional bridge table (PROJECTRELATIONSHIP )with three columns holding the foreign keys to the other three tables (just like an m:n association is represented by an intermediary table with 2 columns). To handle this table with OJB we have to define a class that is mapped on it. This Relationship class can then be used to perform queries/updates as with any other persistent class.