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Tag: database

Hibernate: How to distinguish two uni-directional relationship and one bi-directional relationship?

in this answer, the author said: Take an example of two entities mapped without declaring a owning side: From a OO point of view this mapping defines not one bi-directional relation, but two separate uni-directional relations. 1.My first question is: Why it is not a bi-directional relation? Docs Oracle: In a bidirectional relationship, each entity has a relationship field or

How to generate .dot file using Schemacrawler

Using schemcrawler I’ve generated html file But I want to have an output in .dot file that contains diagram, node, graph, edge etc.. So how can I do it using my code or maybe some another way to do it with Java? Answer Simply change the output format from TextOutputFormat.html to DiagramOutputFormat.scdot. Sualeh Fatehi, SchemaCrawler

Create a table “ca” as a statement using values of another tables but while inserting new values, the values of “ca” doesn’t change

I want to calculate turnover like in new table called ca ‘ I have tables article (idarticle, priceBuying, priceSale, quantity), and table command have (idarticle, quantity, dateSale), I want to calculate turnover automatically everyday and insert into ca , but the problem is when I insert new values into command the values of ca not updating using oracle db. Answer

Understanding how to model UML Class/Database

I’m confused with designing a client software with database integration to what should be a member variable of the class or just a query to the database. Let me be specific with a trivial example: If I have, lets say, a Student class, which has a list of “friends” that are Student objects. Should my software design have an ArrayList<Student>

executeUpdate() returns always 1 with MERGE statement

ExecuteUpdate() is always returning 1. Pls suggest and appreciate any input. Procedure: Java code: stmt.executeUpdate() – always returns 1, even though insertion happens only once. Appreciate any inputs on this. Ideally, if there are no insertions or errors, it should return 0 or any exception trace. Pls, suggest.** Answer We can make the column a primary key. Now when multiple