Cego

Cego is an open source and totally free command-line software written in C++, using an object-oriented designed for implementing a relational database that supports transactional SQL query requests in common programming languages, such as C, C++, DBD, and Java.

The application is engineered in such a way that it provides support for a distributed database shadowing feature that is used in some commercial products. It is capable of implementing indexes, views, stored procedures, as well as foreign keys.

Multi-threaded system architecture based on POSIX threads

Its system architecture is multi-threaded, based on POSIX threads, and designed from the ground up for high end availability and performance. Overall, the software provides functionality that exists only on high-end commercial products.

For a detailed description of the database, please see the online documentation available on the project's homepage, in the dedicated documentation section (user guide).

Getting started with Cego

Being a quite popular project, Cego can be easily installed from the default software repositories of your GNU/Linux distribution. So, just open your favorite package manager, search for the ‘cego’ package and install it. After installation, you will be able to use it via a Linux terminal emulator application.

If your distro doesn’t include the Cego package, you must download the latest version from Softoware or the official website, save it on a location of your choice, extract its contents, open a Linux Terminal window and navigate to the location of the extracted archive files using the ‘cd’ command.

Then, type the ‘./configure && make’ command to optimize and compile the app’s source code for a specific hardware architecture and/or operating system. After an errorless compilation, you must type the ‘make install’ command as root, or with sudo, to make the software available to all users. Use the ‘cego --help’ command to view the program’s command-line options.

What is new in this release:

• Added utility function blobsize for retrieving blob size information.

What is new in version 2.20.6:

• Added fix in CegoFunction::evalFieldValue for SUBSTR case to avoid stringbuf exceed exception. start and len parameters are set to string boundaries in case of invalid user input.
• Added csmode and qescmode flags for cego xml initialization Exception message fix in CegoFactor::evalFieldValue.

What is new in version 2.20.4:

• Added hitrate calculation to buffer pool information.
• Added transitive role removal for all users, if a role is dropped.
• Added many improvements to curses based administration frontent ( cgadm ) Now tableset, user and role administration can be done supported by an curses based GUI. Null value check added for "alter table" command, so in case of modification of an attribute to be not null, the table entries are checked for it (new method CegoTableManager::checkNullValue)
• Cleanup in CegoObjectManager ( introduced method getHashPageId) Fixes for table altering : In case of renaming table attributes, the corresponding key entries for index, btrees, fkey and checks have not been modified.

What is new in version 2.20.3:

• Fixes added in CegoBufferPool::writeAndRemoveTabSet and CegoBufferPool::writeCheckPoint so just pages are written, which are occupied. Otherwise, this may lead to system crash, if pages which have been released ( marked as NOT_OCCIPIED ) and written to disk.

What is new in version 2.20.2:

• Fixed a problem in CegoFileHandler::allocatePage If a page is allocated with doAppend == false, the append pointer is reset. Otherwise, freed pages are never reallocated again and sustained create/drop operations may lead to page exceed.

What is new in version 2.20.1:

• Fix for btree objects. In some cases, bufferUnfix operations have not been done correcty, which might result in corrupted btree objects.

What is new in version 2.20.0:

• The CegoBTreeManager::deleteBTree method has been redesigned. In case of non-unique index objects, it might happen, that the corresponding index entry was not found ( if the value is spreaded over several leaf nodes ) This problem is fixed with the new method implementation
• Added relevance attribute value for btree object. This allows to make a better decision about the relevance of a btree object which results in an optimized query execution plan.

What is new in version 2.19.14:

• Functional expansion for aggregation queries to support aggregation in functions e.g. select f1(sum(a)) from t1.

What is new in version 2.19.13:

• Further corrections for CegoDatabaseManager::useObject method numTries was not increased correctly.
• Optimization for CegoTableManager::deleteDataTable The index evaluation was not correct, so the faster deletion strategy for tables without index objects was not used.

Requirements:

• base-1.0.4.tar.gz
• xml-1.0.1.tar.gz