OpenBaseMovil
Welcome at » FAQ

FAQ

Categories

1. General

1.1 What are the hardware requirements for OpenBaseMovil?

You just need a JTWI 1.0 compatible phone ( MIDP 2.0 and CLDC 1.0). JTWI states that no limits should be imposed in the number of total number of different RecordStores, but that a minimum of 5 must be provided. To create useful j2me database powered applications the phone should have a greater limit, but that is not usually a problem.

2. J2ME Database

2.1. What are the known limits for the number of tables and rows per table in OpenBaseMovil-db?

There are no imposed limits, so the real one is the phone the applications runs in. Many phones such as all Nokia S60 and SonyEricsson JP5 and onwards let J2ME applications use as many flash memory as available, with no limit in the RecordStore size. Other phones such as Nokia S40, BlackBerry and almost all Motorola, put a limit in one or both planes: they al limit the maximum size of a single RecordStore to sizes varying from 32Kb to 512Kb, and some (Motorola mainly) also impose a limit of about 5Mb to the memory available to J2ME applications.

The next version of the OpenBaseMovil-storage, the library that handles RecordStore access for OpenBaseMovil-db, will include a file splitting mechanism to override this limitation of the maximum RecordStore size. The current version detects the maximum size limit and when it’s bellow 1Mb it applies compression to the data, so you can expect a gain of approx. between 30% and 50% of space in these situations.

2.2. Has OpenBaseMovil-db SQL support?

Not yet, but is planned to have a subset of the SQL standard in future releases. It now uses a very simple, JDBC-like, API to manage the database structure and data.

2.3. Does OpenBaseMovil-db have support for full-text indexes?

Yes. You must keep in mind that J2ME devices are constrained ones, so the full-text capability has it’s limitations. OpenBaseMovil-db full text indexes index each word on the selected fields and let you search for one or more terms that would be used as a “contains a word that starts with” filter. For example, “choc” would match “chocolate cake” and “white chocolate” but not “superchocolate”; and “choc ca” would only match “chocolate cake” from the above.

2.4. What are average seek times?

It depends a lot on the phone, but for example, using a SonyEricsson K610 the average seek times for direct search indexes are between 3ms and 20ms, and for full text indexes are between 50ms and 120ms. This tests where conducted over tables with around 1500 rows, but we’ve found that for 10000 rows the times just raise around 1ms or 2ms.

2.5. Is there a synchronization engine available?

Yes, but not under the OpenBaseMovil project. The original and parent project BaseMovil was built around a very powerful synchronization engine that is capable of creating and updating the database structure, populate and synchronize in both ways (device <-> server) all the data in a personalized way (per user), and also connect to any back-end system like ERPs or CRMs.
The Developer Program for BaseMovil is free to join and you can create, host and distribute your applications through our systems. More about this in the Licensing page.