Why Using Top Link is best in DB Adapter?

Question

Hi All,
Can any one suggest , Why Using Top Link (Build-in Insert, Select etc. operation) is best in DB Adapter over using custom query?
Thanks

Answer 1

Hi Vikky,
for insert/select it depends on what kind of user you are. TopLink lets you browse and click on a tables and have everything generated for you. If you are more a DBA or show me the SQL type then you can just type SQL directly.
Some advantages of TopLink would be:
-The range of SQL generated by TopLink is limited, but if you hard code complex SQL into your service you need to maintain it.
-TopLink can generate at runtime the correct SQL for a given database, making switching from say DB2 to Oracle easy.
-The merge operation will compare the input XML to the columns on the database and update only what has changed. It can also do a sparse merge. If only 4 columns in the XML were set, only those 4 columns in the database will be updated.
-For inbound polling the strategy used (LogicalDelete, Sequencing Table, etc) is a configuration property and then at runtime multiple SQL statements are generated. The SQL also takes advantage of advanced syntax like the Oracle-only FOR UPDATE SKIP LOCKED, writing it all yourself may be tedious and error prone.
-The main benefit of TopLink is when you go beyond thinking about a single table. If you import multiple related tables at once, TopLink will generate the SQL to select from and maintain multiple tables, establish a commit order, and generate a hierarchical XSD. With custom SQL the matching XSD is always flat. I.e. if you just need to insert an emp you could get away with custom SQL. If you need to insert a dept and emps, I would use TopLink.
-This is also when the intermediary abstraction of an object/table makes more sense, as you only need to import a complex relational schema once, then generate inserts, selects, etc.
So I hope that helps. They are each equally viable and can do something that the other can't. Where you see an overlap I would go with personal preference.
Thanks
Steve