question: protected ForeignKeyConstraint buildForeignKeyConstraint ( List < String > fkFieldNames , List < String > pkFieldNames , TableDefinition targetTable , DatabasePlatform platform ) { assert fkFieldNames . size ( ) > 0 && fkFieldNames . size ( ) == pkFieldNames . size ( ) ; ForeignKeyConstraint fkConstraint = new ForeignKeyConstraint ( ) ; for ( int i = 0 ; i < fkFieldNames . size ( ) ; i ++ ) { fkConstraint . getSourceFields ( ) . add ( fkFieldNames . get ( i ) ) ; fkConstraint . getTargetFields ( ) . add ( pkFieldNames . get ( i ) ) ; } fkConstraint . setTargetTable ( targetTable . getFullName ( ) ) ; String fkFieldName = fkFieldNames . get ( 0 ) ; String name = buildForeignKeyConstraintName ( this . getName ( ) , fkFieldName , platform . getMaxForeignKeyNameSize ( ) , platform ) ; fkConstraint . setName ( name ) ; return fkConstraint ; }
target:  Build a foreign key constraint.