Man:
man command formats and displays the on-line manual pages. If you specify section, man only looks in that section of the manual. name is normally the name of the manual page, which is typically the name of a command, function, or file.
$ man whatis
whatis(1) [...]
Man, Whatis and Apropos
SQL Developer: Database Export Wizard to export DDL and Data as DML
Sometimes, you would want to generate a script that you would like to run repeatedly in many environments for many objects. In such situations, use of Database Export wizard helps you generate DDL and DML (INSERT) script; – you can select object types, specific objects and filter out or restrict the data exported.
Step1: Source / [...]
Removing table rows using an inline view
The SQL standard allows you to use an inline view in a DELETE statement, see the pseudo form below – If a condition such as key-preserved table is not met then it will result in error, “ORA-01752: cannot delete from view without exactly one key-preserved table.”
DELETE (SELECT some_column FROM table_one JOIN table_two USING (join_column));
I would [...]
Software Performance and Scalability: A Quantitative Approach
Software Performance and Scalability: A Quantitative Approach (Wiley, May 2009) is for people involved in designing, developing, testing, implementing and managing enterprise applications. This book provides the necessary quantitative foundation, analytical and measurement aspects of performance and scalability - effective blend of studies and practical examples, which makes it thorough, it easier to read and informative.
Author [...]
Joins, Join Conditions, Filters and Join Types
Joins
A join is a query that combines rows from two or more tables. Oracle performs a join whenever multiple tables appear in the FROM clause of the query. Below is a SQL join statement, legacy syntax and ANSI/ISO syntax (also referred as new join syntax, was first introduced in Oracle 9i release) in a simple [...]
Data Quality: The Accuracy Dimension
Data quality is an important element in data management; it is a larger topic by itself. If you are looking for a book on data quality, don’t look further. Get a copy of Data Quality: The Accuracy Dimension (Morgan Kaufmann; 1st Edition, 2003).
This book is about data accuracy, divided into three parts – Part 1 [...]
Virtual / NOSEGMENT / Fake Indexes
Virtual Indexes (aka NOSEGMENT Indexes or Fake Indexes) are useful to check whether the creation of an Index affects the execution plan with out having to create the actual index. Virtual index is just a definition without a physical index segment so it does not consume disk space. Additionally, virtual index is available to a [...]
ORION: Oracle I/O Numbers Calibration Tool in Oracle 11g R2
ORION (Oracle I/O Calibration Tool) is a standalone tool for calibrating the I/O performance for storage systems that are intended to be used for Oracle databases. The calibration results are useful for understanding the performance capabilities of a storage system, either to uncover issues that would impact the performance of an Oracle database or to [...]
Customizing TOAD SQL Explain Plan Content
The default display of Explain Plan in TOAD SQL Editor has very basic information.
Right-clicking on the explain plan and selecting “Adjust Content” from the context menu will bring “Execution Plan Preferences” window, which allows you to control the information displayed in the Explain Plan tab.
Optimizer Index Access Paths: Why Oracle is not using my Index?
Access paths are ways in which data is retrieved from the database. In general, index access paths should be used for statements that retrieve a small subset of table rows, while full scans are more efficient when accessing a large portion of the table. Online transaction processing (OLTP) applications, which consist of short-running SQL statements [...]