SQLJet is an independent pure Java implementation of a popular SQLite database management system. SQLJet is a software library that provides API that enables Java application to read and modify SQLite databases.
SQLJet does not support SQL queries; there is an API to work with the database on a lower level.
Drizzle is a community-driven open source project that is forked from the popular MySQL database. The Drizzle team has removed non-essential code, re-factored the remaining code and modernized the code base moving to C .
Xml based metalanguage for a database schema definition. The following artifacts could be generated from this definition: DDL scripts for various database servers, HTML - documentation, ERD.
Sausalito is a product that enables you to develop, test, deploy, and host scalable web applications in the cloud. On this page, you find some reading material in case you're interested in
* technical details about Sausalito,
* user experience reports, or
* presentations and demos that we gave.
AutoPatch was born from the needs of using an agile development process while working on systems that have persistent storage. Without AutoPatch, developers usually can't afford the maintenance headache of their own database, and DBAs are required just to apply changes to all of the various environments a serious development effort requires.
The very application of database changes becomes an inefficient, error-prone, expensive process, all conspiring to discourage any refactoring that touches the model, or being a bottleneck when model changes are made.
AutoPatch solves this problem, completely.
With AutoPatch, an agile development process that requires a database change looks like this:
* Developer alters the model, which requires a change to the database
* Developer possibly consults a DBA, and develops a SQL patch against their personal database that implements the alteration
* Developer commits the patch to source control at the same time as they commit their dependent code
* Other developers' and environments' databases are automatically updated by AutoPatch the next time the new source is run
This represents streamlined environment maintenance, allowing developers to cheaply have their own databases and all databases to stay in synch with massively lower costs and no environment skew.
That's what AutoPatch does.
Clusters with one database? Multiple schemas? Logical migrations, instead of just DDL changes? Need to do something special/custom? Need to distribute your changes commercially? All without paying anything? No problem.
Neo4j is a graph database. It is an embedded, disk-based, fully transactional Java persistence engine that stores data structured in graphs rather than in tables. A graph (mathematical lingo for a network) is a flexible data structure that allows a more agile and rapid style of development.
You can think of Neo4j as a high-performance graph engine with all the features of a mature and robust database. The programmer works with an object-oriented, flexible network structure rather than with strict and static tables — yet enjoys all the benefits of a fully transactional, enterprise-strength database.
Neo4j is released under a dual free software/commercial license model (which basically means that it’s “open source” but if you’re interested in using it in commercially, then you must buy a commercial license).
Neo4j has been in commercial development for 8 years and in production for over 5 years. It is a mature and robust graph database that provides:
* an intuitive graph-oriented model for data representation. Instead of static and rigid tables, rows and columns, you work with a flexible graph network consisting of nodes, relationships and properties.
* a disk-based, native storage manager completely optimized for storing graph structures for maximum performance and scalability.
* massive scalability. Neo4j can handle graphs of several billion nodes/relationships/properties on a single machine and can be sharded to scale out across multiple machines.
* a powerful traversal framework for high-speed traversals in the node space.
* a small footprint. Neo4j is a single <500k jar with one dependency (the Java Transaction API).
* a simple and convenient object-oriented API.
* optional layers to expose Neo4j as an RDF store, i.e. easily inject / extract data as RDF, express meta model semantics using OWL and query the node space using SPARQL. When it comes to scalability numbers, remember that several triples are usually mapped to a single node. (currently being developed under the umbrella of the OpenMetadir project)
Very interesting approach!
"Apache Empire-db is an Open Source relational data persistence component which allows database vendor independent dynamic query definition as well as safe and simple data retrieval and updating. Compared to most other solutions like e.g. Hibernate, TopLink, iBATIS or JPA implementations, Empire-db takes a considerably different approach, with a special focus on compile-time safety, reduced redundancies and improved developer productivity."
The Apache Hadoop project develops open-source software for reliable, scalable, distributed computing, including:
* Hadoop Core, our flagship sub-project, provides a distributed filesystem (HDFS) and support for the MapReduce distributed computing framework.
* HBase builds on Hadoop Core to provide a scalable, distributed database.
* Pig is a high-level data-flow language and execution framework for parallel computation. It is built on top of Hadoop Core.
* ZooKeeper is a highly available and reliable coordination system. Distributed applications use ZooKeeper to store and mediate updates for critical shared state.
* Hive is a data warehouse infrastructure built on Hadoop Core that provides data summarization, adhoc querying and analysis of datasets.
What CouchDB is
* A document database server, accessible via a RESTful JSON API.
* Ad-hoc and schema-free with a flat address space.
* Distributed, featuring robust, incremental replication with bi-directional conflict detection and management.
* Query-able and index-able, featuring a table oriented reporting engine that uses Javascript as a query language.
What it is Not
* A relational database.
* A replacement for relational databases.
* An object-oriented database. Or more specifically, meant to function as a seamless persistence layer for an OO programming language.
Relational databases define a strict structure and provide a rigid way to maintain data for a software application. Apache's open source CouchDB offers a new method of storing data, in what is referred to as a schema-free document-oriented database model. Instead of the highly structured data storage of a relational model, CouchDB stores data in a semi-structured fashion, using a JavaScript-based view model for generating structured aggregation and report results from these semi-structured documents. CouchDB has been developed from the ground up with Web applications as the primary focus and has its sights on becoming the de-facto database for Web application development.
A library for using Memcached as a second level distributed cache in Hibernate.
* Based on the excellent spymemcached client
* Includes support for the Whalin (danga) memcached client
* Supports entity and query caching.
* See the Configuration page
* See how easy it is to configure in Grails
The project provides extensions to Hibernate to provide complete auditing capabilities. It uses a set of tables in the DB that do not depend on the object model
Das Problem …
PHP-Scripte werden nach einer bestimmten Laufzeit abgebrochen (normalerweise nach 30 Sekunden), und so funktioniert ein Backup mit diversen Tools nur bis zu einer bestimmten Größe.
Braucht das Script länger als die 30 Sekunden, so wird es vom Server einfach abgebrochen, und man kommt nicht mehr an sein Backup heran. Gleiches gilt für das Wiedereinspielen eines Backups.
Wer einmal ein Dumpfile von Hand in viele kleinere Einzelabschnitte zerlegt hat, um eine Datenbank wieder herzustellen, der weiß genau, wovon wir reden.
MySQLDumper ist die Lösung …
MySQLDumper umgeht den Timeout-Error mit Hilfe eines kleinen Tricks: Er liest nur eine bestimmte Anzahl von Datensätzen aus der Tabelle aus, merkt sich, wie weit er gekommen ist, und ruft sich anschließend selbst auf. Dadurch erhält das Script bei jedem Aufruf wieder die vollen 30 Sekunden und umgeht so den Timeout-Error. Das gleiche Prinzip benutzt MySQLDumper auch beim Wiederherstellen der Daten.
MySQLDumper kann die Daten beim Sichern sofort packen. Auch das Wiederherstellungsscript kann direkt aus dieser gepackten Datei lesen, ohne dass sie auf dem Server entpackt werden muss! Natürlich kann man die Datei auch ungepackt lassen, aber spätestens beim Hochladen eines Backups weiß man dies zu schätzen.
DbFit is a set of FIT fixtures which enables FIT/FitNesse tests to execute directly against a database. This enables developers to manipulate database objects in a relational tabular form, making database testing and management much easier then with xUnit-style tools. The library is free to use, released under GNU GPL.
Hibernate Spatial is a generic extension to Hibernate for handling geographic data. Hibernate Spatial is open source and licensed, like Hibernate, under the LGPL license.
Hibernate Spatial allows you to deal with geographic data in a standardized way. It abstracts away from the specific way your database supports geographic data, and provides a standardized, cross-database interface to geographic data storage and query functions.
Hibernate Spatial supports most of the functions of the OGC Simple Feature Specification. Supported databases are: Oracle 10g/11g, Postgresql/Postgis, and MySQL.
Spring, JPA, and JTA with Hibernate and JOTM
2007-04-24 20:35
have been struggling for a couple of hours today to modify a Spring JPA configuration with a single datasource, Hibernate as the JPA provider and the JpaTransactionManager to a configuration with two XA datasources, Hibernate as the JPA provider, and the JtaTransactionManager with JOTM as the standalone JTA provider.
since the Spring and Hibernate reference manual and Javadoc documentation merely contain a number of hints on how to configure JPA with a JTA transaction manager and others are struggling as well i decided to post how i finally got it to work.
Many enterprise business applications have such requirements that they should log their users' operations; who performs and when, records that are inserted into, deleted from database, or are changed during those operations, with a meaningful description about current state of those records. Hibernate already provides an interceptor mechanism at SessionFactory level. Hibernate fires events indicating new records are inserted, old ones are deleted, detection of updates, and other events related with transaction status, session flush etc. By that way one can easily track changes on persistent entities in his application.
The agimatec tools contain some utilities to enable generation of files, source code etc. from sql files and annotated java classes.
The agimatec-dbmigrate tool is a database migration/script execution framework that can execute sql scripts, groovy scripts and provides a lot of features to assist in database schema migration. (tested with Oracle and Postgres)
The Envers project aims to enable easy versioning of persistent JPA classes. All that you have to do is annotate your persistent class or some of its properties, that you want to version, with @Versioned. For each versioned entity, a table will be created, which will hold the history of changes made to the entity. You can then retrieve and query historical data without much effort.
Similarly to Subversion, the library has a concept of revisions. Basically, one transaction commit is one revision (unless the transaction didn't modify any versioned entities). As the revisions are global, having a revision number, you can query for various entities at that revision, retrieving a (partial) view of the database at that revision.