<p>i work with sql server, but i must migrate to an application with Oracle DB.
for trace my application queries, in Sql Server i use wonderful Profiler tool. is there something of equivalent for Oracle?</p>

Oracle, along with other databases, analyzes a given query to create an execution plan.  This plan is the most efficient way of retrieving the data.
Oracle provides the '
```
explain plan
```
' statement which analyzes the query but doesn't run it, instead populating a special table that you can query (the plan table).
The syntax (simple version, there are other options such as to mark the rows in the plan table with a special ID, or use a different plan table) is:
```
```
explain plan for <sql query>
```
```
The analysis of that data is left for another question, or your further research.