Search results
Results from the WOW.Com Content Network
A simple example would be a database having tables sales2005 and sales2006 that have identical structures but are separated because of performance considerations. A UNION query could combine results from both tables. Note that UNION ALL does not guarantee the order of rows. Rows from the second operand may appear before, after, or mixed with ...
The nested set model is a technique for representing nested set collections (also known as trees or hierarchies) in relational databases.. It is based on Nested Intervals, that "are immune to hierarchy reorganization problem, and allow answering ancestor path hierarchical queries algorithmically — without accessing the stored hierarchy relation".
UPDATE table_name SET column_name = value [, column_name = value ... ] [ WHERE condition ] For the UPDATE to be successful, the user must have data manipulation privileges ( UPDATE privilege) on the table or column and the updated value must not conflict with all the applicable constraints (such as primary keys , unique indexes, CHECK ...
A version where MySQL has been replaced by PostgreSQL is called LAPP, or sometimes by keeping the original acronym, LAMP (Linux / Apache / Middleware (Perl, PHP, Python, Ruby) / PostgreSQL). [7] The LAMP bundle can be combined with many other free and open-source software packages, including: netsniff-ng for security testing and hardening
CRUD is also relevant at the user interface level of most applications. For example, in address book software, the basic storage unit is an individual contact entry. As a bare minimum, the software must allow the user to: [6] Create, or add new entries; Read, retrieve, search, or view existing entries; Update, or edit existing entries
SELECT * FROM database1. foo vs. SELECT * FROM database2. foo (no explicit schema between database and table) SELECT * FROM [database1.] default. foo vs. SELECT * FROM [database1.] alternate. foo (no explicit database prefix) The problem that arises is that former MySQL users will create multiple databases for one project. In this context ...
It was developed by MySQL AB, and enables users to graphically administer MySQL databases and visually design database structures. Adminer – free MySQL front end capable of managing multiple databases, with many CSS skins available. It is a light-weight alternative to phpMyAdmin, distributed under the Apache license (or GPL v2) as a single ...
SELECT list is the list of columns or SQL expressions to be returned by the query. This is approximately the relational algebra projection operation. AS optionally provides an alias for each column or expression in the SELECT list. This is the relational algebra rename operation. FROM specifies from which table to get the data. [3]