{"id":949,"date":"2010-01-15T00:52:09","date_gmt":"2010-01-14T23:52:09","guid":{"rendered":"http:\/\/www.gamlor.info\/wordpress\/?p=949"},"modified":"2021-03-11T09:45:22","modified_gmt":"2021-03-11T08:45:22","slug":"db4o-tools-for-adhoc-querying-and-modification","status":"publish","type":"post","link":"https:\/\/www.gamlor.info\/wordpress\/2010\/01\/db4o-tools-for-adhoc-querying-and-modification\/","title":{"rendered":"db4o: Tools For Adhoc Querying And Modification"},"content":{"rendered":"

\"\"<\/a>Remember my very first post<\/a> about db4o? There I\u2019ve made the statement that the tool-support is very bad. Well I don\u2019t revise my opinion here. The situation is still bad compared to the relational database world. Mostly that’s because relational databases have a giant user base, are well known and have some common interfaces (JDBC, ODBC, etc).<\/p>\n

(All posts of this series: the basics<\/a>, activation<\/a>, object-identity<\/a>, transactions<\/a>, persistent classes<\/a>, single container concurrency<\/a>, Queries in Java, C# 2.0<\/a>, client-server concurrency<\/a>, transparent persistence<\/a>, adhoc query tools<\/a>)<\/p>\n

Now enough complaining. Only complaining doesn\u2019t help anyway!\u00a0 In this post I\u2019ll introduce two tools and show briefly, what you can do with them. Let\u2019s start:<\/p>\n

ObjectManager Enterprise (OME)<\/h4>\n

This is a tool which comes bundled with db4o<\/a>. In the Java-Version it\u2019s a Eclipse-plugin. In the .NET-version it\u2019s a Visual Studio add-on.<\/p>\n

For the .NET-version there are installers in the \u2018ome2005\u2019 and \u2018ome2008\u2019-directory of the db4o-distribution. Pick the one which corresponds to your Visual Studio version and install it. After restarting Visual Studio, you\u2019ve a new buttons in you\u2019re toolbar and a new menu-point \u2018Tools\u2019->\u2019ObjectManager Enterprise\u2019.<\/p>\n

For the Java-Version there\u2019s a zip-file in the \u2018ome\u2019-directory of the db4o-distribution. Unzip it somewhere. Open Eclipse, go to \u2018Help\u2019->\u2019Install New Software\u2019. Click on \u2018Add\u2019, then \u2018Local\u2019 and choose the directory you\u2019ve unzipped the zip-file before. The click just through all the confirm-dialogs etc. Then restart Eclipse. Now there\u2019s a new menu-point \u2018OME\u2019 in Eclipse.<\/p>\n

Now you can connect to a db4o-database. Either you can connect to a running db4o-server or open a db4o-database-file directly.<\/p>\n

\"\"<\/a><\/p>\n

Queries with OME<\/h4>\n

Now in the OME you don\u2019t use a query-language for querying the database. This is quite a surprise. So how do you build queries then? You build then by drag and drop! On the left the OME shows a list of all known classes. When you expand such a class, you see the fields. Fields which are no primitives can be extended further. To build a query you choose a object-type, lets say \u2018Person\u2019. Then you expand the \u2018Person\u2019-class on the left, choose the fields you want to query and drag them into the \u2018Query-Builder’-window. After sticking the criterions together, you can run the query. Furthermore you also can update field of persisted data.<\/p>\n

Here a little screen-cast, which shows this:
\n