Introduction to Oracle SQL Developer
A collection of FAQ to introduce Oracle SQL Developer, the new free GUI client for DBA and developers. This FAQ can also be used as learning tutorials on SQL statement execution, data objects management, system views and reports, stored procedure debugging.

Introduction to Oracle Database 10g Express Edition
This is a collection of FAQ on Oracle 10g XE (Express Edition) with installation and basic introduction. The answers and sample scripts provided can be used as learning tutorials or interview preparation guides.

Managing Oracle Tablespaces and Data Files
This is a collection of FAQ for Oracle DBA on creating and managing tablespaces and data files. The clear answers and sample scripts provided can be used as learning tutorials or interview preparation guides.

Creating New Database Instance Manually
This is a collection of FAQ for Oracle DBA on creating Oracle database instances manually using CREATE DATABASE statement. Items in this FAQ collection are organized together to form a complete tutorial guide on creating a new database instance manually.

Expert One-on-One: Oracle: Part 1
This manuscript is Chapter 1 "Developing Successful Oracle Applications" from the Wrox Press book Expert One on One: Oracle. This first part covers developing successful Oracle applications and the Black Box approach.

Expert One-on-One: Oracle: Part 2
This manuscript is Chapter 1 "Developing Successful Oracle Applications" from the Wrox Press book Expert One on One: Oracle. The second installment covers understanding Oracle architecture, using bind variables, understanding concurrency control, and multi-versioning.

Expert One-on-One: Oracle: Part 3
This third installment looks at database independence, the impact of standards, features and functions, and solving problems simply. This manuscript is Chapter 1 "Developing Successful Oracle Applications" from the Wrox Press book Expert One on One: Oracle.

Expert One-on-One: Oracle: Part 4
This fourth and final installment looks at making the database run faster and the DBA-developer relationship. This manuscript is Chapter 1 "Developing Successful Oracle Applications" from the Wrox Press book Expert One on One: Oracle.

Introduction and Examples to Oracle Advanced Queueing
Oracle introduced powerful queuing mechanisms where messages can be exchanged between different programs. They called it Advanced Queuing AQ. Exchanging messages and communicating between different application modules is a key functionally becoming important as soon as we leave the database servers SQL and PL/SQL programming domain.

Global Statistics vs. Histograms with DBMS_STATS Package
Optimisation is the process of choosing the most efficient way to execute a SQL statement. The cost-based optimiser uses statistics to calculate the selectivity of predicates and to estimate the cost of each execution plan.

Analytic Functions in Oracle 8i and 9i
Analytic Functions, which have been available since Oracle 8.1.6, are designed to address such problems as "Calculate a running total", "Find percentages within a group", "Top-N queries", "Compute a moving average" and many more. Most of these problems can be solved using standard PL/SQL, however the performance is often not what it should be. Analytic Functions add extensions to the SQL language that not only make these operations easier to code; they make them faster than could be achieved with pure SQL or PL/SQL.

Parallel Clause and Small Tables
If you have multiple CPUs available you may come up with the idea to set parallel execution on every table. The Oracle Optimizer should decide about the degree of parallelism or even if is necessary to use parallel execution at all. What's a great thing on big tables shows up badly on small ones. The split up of all the work over more than one CPU may result in an overhead which exceeds the execution time needed by one CPU by factors. While the Optimizer recognises for index accesses not to use parallel execution it doesn't for full table scans. This sounds reasonable at first hand but consider that often full table scans are the fastest option on smaller tables.

How to specify the WHERE clause for UPDATE / DELETE
Sometimes multiple users are accessing the same tables at the same time. In these situations, you need to decide when to allow your application to update the database. If you allow your application to always update the database it could overwrite changes made by other users. You can control when updates succeed by specifying which columns are included in the WHERE clause of an UPDATE or DELETE statement.

How to measure Index Selectivity
B*TREE Indexes improve the performance of queries that select a small percentage of rows from a table. As a general guideline, we should create indexes on tables that are often queried for less than 15% of the table's rows. This value may be higher in situations where all data can be retrieved from an index, or where the indexed columns can be used for joining to other tables.

Primary Keys and Unique Columns in Oracle and SQL-Server
The SQL-92 standard requires that all values in a primary key be unique and that the column not allow null values. Both Oracle and Microsoft SQL Server enforce uniqueness by automatically creating unique indexes whenever a PRIMARY KEY or UNIQUE constraint is defined. Additionally, primary key columns are automatically defined as NOT NULL. Only one primary key is allowed per table.