Implicit Conversion And ORA-01722

I’ve an email from a reader that he gets ORA-01722 error from a query. he says that the query works well on same structured tables on different schemas. After a short conversation, I figured out that it’s about implicit conversion mechanism.

Let’s create a sample table to demonstrate the problem:

You may notice that we use “varchar” column to keep “number” values. That was the exact case my reader faced.

Let’s write a simple query:

Oracle 11g New Feature: RMAN Data Recovery Advisor

In Oracle 11g, RMAN provides a new advisor called Data Recovery Advisor (DRA). DRA has several new commands to help DBAs for performing recovery tasks.

To list of database failures, you can issue:

DRA will consolidate related failures into a single failure. You can list a failure individually by issuing “list failure X detail” command.

Optimum Size of The Online Redo Log Files

The Oracle Database Performance Tuning Guide recommends switching logs at most once every twenty minutes. If our online redo logs switch once every 10 minus during peak hours, our redo logs should be increased to 2 times larger then their current size.

Here’s a simple query for calculating recommended size of redo log files:

How to Develop Java Stored Procedures

I’ll try to demonstrate how we can use loadjava to load our Java class into Oracle Database and use its methods as stored procedures. Before we begin to write the Java codes, I’ll create a simple table. When I call my java stored procedure, it will insert a record to this table.

I created this table in HR schema because I’ll load my java object in HR schema. If you’ll use another schema, then do not forget to load your java code in same schema or set required permissions. This is the main method I’ll use as my stored procedure:

Application Express URL Syntax

The URLs are automatically constructed by APEX, so in most cases we do not need to understand the syntax nor modify it. On the other hand, understanding how URL (f?p) syntax works can be useful while defining hypertext links to the pages.

Let’s take a look at the parameters send as variable “p”:


App: Uniquely identified application ID

Page: Unique page ID

Session: Randomly generated session ID – to keep your session information.

Request: The value of REQUEST. When you click a button, the value of REQUEST will keep the name of the button. Bind variable: :REQUEST

Debug: DEBUG flag. Setting this flag to YES displays details about application processing.

ClearCache: Clears the cache if you specify he numeric page number.

ItemNames: Comma-delimited list of item names (stored in user’s session).

ItemValues: List of item values (stored in user’s session)

PrinterFriendly: If it’s set to YES, the page is rendered in printer friendly mode.