Tutorial Mapping Query

[Mikaël Cluseau]

Hello there,

I was going around 3.0M1, gone on the quick starts to see how it is ;-)

I have been a bit disappointed by the "Main.java" code snippet :

QueryChain chain = new QueryChain();
chain.addQuery(new NamedQuery("DeleteAll", Collections.singletonMap(
                "table",
                "PAINTING")));
chain.addQuery(new NamedQuery("DeleteAll", Collections.singletonMap(
                "table",
                "ARTIST")));
chain.addQuery(new NamedQuery("DeleteAll", Collections.singletonMap(
                "table",
                "GALLERY")));

context.performGenericQuery(chain);

Its a lot of cut-and-paste, compared to the comment "we need to run the
same query three times with different sets of parameters". Wouldn't the
best code for this statement be :

QueryChain chain = new QueryChain();

for (String tableName : new String[] {
     "PAINTING", "ARTIST", "GALLERY"}) {
    chain.addQuery(new NamedQuery("DeleteAll", Collections.singletonMap(
                "table", tableName)));
}

context.performGenericQuery(chain);

Then we could even show people how easy it is to build good APIs with
Cayenne ;-) :

public static void emptyTables(String... tables) {
    QueryChain chain = new QueryChain();
    for (String tableName : tables) {
        chain.addQuery(new NamedQuery("DeleteAll", Collections.singletonMap(
                "table", tableName)));
    }
    context.performGenericQuery(chain);
}

And in the "main" method :

emptyTables("PAINTING", "ARTIST", "GALLERY");

I may go to far for a quick start, but worth to post on the mailing list
anyway ;-)

-- 
Mikaël Cluseau <[EMAIL PROTECTED]>
ISI.NC