Group items tagged

Daffodil Replicator is a Java tool for data synchronization, data migration, and data backup between various database servers. Daffodil Replicator works over standard JDBC driver and supports replication across heterogeneous databases. At present, it supports following databases: Microsoft SQL Server, Oracle, Daffodil DB, DB2, Derby, MySql, and PostGreSql. Daffodil Replicator is available in both enterprise and open source versions referred as Daffodil Replicator(E) and Daffodil Replicator(OS) respectively. For more details on Daffodil Replicator (E) or Daffodil Replicator (OS), click on the links on the left.

SymmetricDS is web-enabled, database independent, data synchronization/replication software. It uses web and database technologies to replicate tables between relational databases in near real time. The software was designed to scale for a large number of databases, work across low-bandwidth connections, and withstand periods of network outage. By using database triggers, SymmetricDS guarantees that data changes are captured and atomicity is preserved. Support for database vendors is provided through a Database Dialect layer, with implementations for MySQL, Oracle, SQL Server, PostgreSQL, DB2, Firebird, HSQLDB, H2, and Apache Derby included. Synchronization can be configured to push data (trickle-back) or pull data (trickle-poll) at an interval. SymmetricDS allows for synchronization between two or more tiers of nodes, such as the following: A farm of web server nodes fronting an enterprise-class general office database A handful of regional servers for synchronizing from the general office to remote geographical areas 1000(s) of store server nodes using a departmental class database to sync with a regional node 10(s) of Point of Sale (POS) register nodes using an embedded database to sync with a store server Deployment options include the following: Web application archive (WAR) deployed to an application server such as Tomcat, Jetty, or JBoss Standalone service Embedded in an application SymmetricDS is written in Java and licensed as open source software under the GNU Lesser General Public License (LGPL).

DdlUtils is a small, easy-to-use component for working with Database Definition (DDL) files. These are XML files that contain the definition of a database schema, e.g. tables and columns. These files can be fed into DdlUtils via its Ant task or programmatically in order to create the corresponding database or alter it so that it corresponds to the DDL. Likewise, DdlUtils can generate a DDL file for an existing database. DdlUtils uses the Turbine XML format, which is shared by Torque and OJB. This format expresses the database schema in a database-independent way by using JDBC datatypes instead of raw SQL datatypes which are inherently database specific. An example of such a file is:

Besides being able to query and manipulate the underlying data management system with Blueprints, a GraphML reader and writer package is provided with Blueprints for streaming XML graph representations into and out of the underlying graph framework. The GraphML package uses StAX to process a GraphML graph. This section discusses the use of the GraphML library for reading and writing XML-encoded graphs.

"The past year I've been learning a lot of Scala and I'm currently working on a new project using Scala. I use LiquiBase, which is a database-independent library for tracking, managing and applying database changes. I'm also using the simple-build-tool (SBT) for my project. So I've put together a little SBT plug-in for running LiquiBase maintenance commands (update, rollback, …) from within SBT. For example, whenever I want to apply new database changes with LiquiBase I can now simply run sbt liquibase-update which sets up a new instance of LiquiBase and executes the LiquiBase update command which migrates my database to the latest version. At the moment the plug-in supports the following commands: liquibase-update, liquibase-drop, liquibase-tag, liquibase-rollback and liquibase-validate. What are the benefits of using the plug-in and not just the LiquiBase CLI? * no download/install of LiquiBase * classpath handled by SBT * no need to provide a big list of parameters or writing shell scripts The plug-in is called liquibase-sbt-plugin and you can find it here on GitHub. Feel free to use it or fork it and suggest changes. I'm still relatively new to Scala and especially SBT so any remarks are very welcome."

There is no migration system in vanilla grails (although possibly in Grails 2.0 …. ?) but there do exist several plugins that provide  some migration functionality. As of this post I am aware of three: dbMigrate, Liquibase, and Autobase. Of these, I prefer Liquibase and cannot recommend it enough. While it uses XML to describe its changesets it is a mature open-source Java project that works flawlessly (and has some excellent documentation). I did not have much luck using DbMigrate and Autobase when including in an existing project… which is a shame as Autobase (which is built on Liquibase) uses a nice DSL syntax to build the migrations.

"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."

t just works - Migrate from any version (incl. an empty database) to the latest version of the schema Automatic migration on startup - Ship migrations together with the application and run them automatically on startup Convention Over Configuration - Classpath Scanning to automatically discover Sql and Java migrations Plain Old Sql - SQL scripts for regular migrations (incl. placeholder replacement). No proprietary XML formats, no lock-in. No limits - Java classes for advanced migrations Highly reliable - Safe for cluster environments (Multiple machines can migrate in parallel) Maven support - Maven plugin for migrating manually Fail fast - Inconsistent database or failed migration prevents app from starting. Schema Clean - Drop all tables, views, triggers, ... from a schema without dropping the schema itself

Apache CouchDB is a document-oriented database that can be queried and indexed in a MapReduce fashion using JavaScript. CouchDB also offers incremental replication with bi-directional conflict detection and resolution. CouchDB provides a RESTful JSON API than can be accessed from any environment that allows HTTP requests. There are myriad third-party client libraries that make this even easier from your programming language of choice. CouchDB's built in Web administration console speaks directly to the database using HTTP requests issued from your browser. CouchDB is written in Erlang, a robust functional programming language ideal for building concurrent distributed systems. Erlang allows for a flexible design that is easily scalable and readily extensible. See the introduction and the technical overview for more information.

Couchbase: The End of the Trade-off Game Before Couchbase, ops teams managing web applications faced tough compromises when it came to databases. Screaming speed or durable, safe data storage. Super scale out virtually overnight or scaling up with lots of hardware upgrades. Bleeding-edge NoSQL or safe, but inflexible relational solutions. Couchbase eliminates those trade-offs. We supply extraordinary speed with complete safety and incorruptibility.  A growth path that will never force you to rethink your application infrastructure from datacenter deployments to mobile devices - one continuous, synchronized flow. Solutions that complement your other systems - including your RDBMS.  Technology that meets the needs of developers and conforms to the mission-critical demands of ops teams. This really is the beginning of a new era of NoSQL solutions. Couchbase: database solutions for a post-relational world. Learn more.

JDBC realm has a lot of attention in recent months. This blog summarizes the evolution of the JDBC realm implementation in GlassFish and explains how the latest implementation works. I would like to thank Jean-Baptiste, and Richter for their contributions and comments. The participation from the open source community definitely helps everyone. I encourage all of you to give feedback, participate, and help evolve this feature further. GlassFish always had the capability for anyone to plug-in a realm. Implementing a custom realm in the Sun Java System Application Server EE 8.0 is described in the article Authentication Using Custom Realms in Sun Java System Application Server. In S1AS 7.x, there is a JDBC Realm bundled in sample. Jean-Baptiste formally filed an enhancement and provided a clear text version of JDBCRealm for GlassFish. Richter wrote another implementation because the GlassFish JDBCRealm at that time not compatible with Tomcat.