The need for device-level search and how to integrate a data manager into a device application.
Savvy embedded developers are multiply the amount of content.
In the movies space, the advent of cheap digital film cameras and editing equipment has led to an explosion in amateur video. YouTube is the definitive example.
Following the general decline in people's attention spans, a "typical" video program is rapidly shifting from the Instead of content coming only from a handful of studios, videos are an explosion in still photography and musical content. Even the volume of commercially-produced broadcast content is exploding. Satellite and cable packages now may contain hundreds of channels.
promises to increase this Why should an embedded developer care about this? Surely Google has the search problem under control? Well, yes, but only if you are searching content on the Web, and only if you have an Internet connection, which can't always be assumed.
Increasingly, content is being downloaded to handheld portable devices. These devices are now storing so much data that finding the content that the user wants is becoming a challenge. Here's a fact that actually finding music on an player is a bit of a chore, so it is easier to just randomize it?
information, and the real value comes from integrating all that data.
engineer. It needs to integrate customer data, product data, service data, location data, and inventory data to be able to answer an obvious have the likely parts in my truck.
" RAM capacity and processing power, driven by the so far inexorable months. This increased power can be used to drive increasingly sophisticated search, and users of both consumer and commercial devices are going to want it. The question is how to best provide it.
But this is not as simple a solution as it seems, and nor is it necessarily the best use of scarce development resources. This article shared updateable data is hard to do well. Training in device software manager.
While it is reasonably easy to write a search solution for a given requirements, it is very hard to write an efficient, compact, general purpose data manager.
core competency? Just as in almost all cases embedded developers use COTS operating systems rather than writing their own, so the time has of simple data sets.
An application that saves the preferences of several users could benefit from this approach. An example could be the code that manages seat and mirror positioning in a passenger vehicle, retaining the settings for several drivers. The application is simple, for application objects.
An ODBMS can make object-oriented programming objects between persistent storage and RAM. While some ODBMS provide limited search capability, this is not their strength. Objects are An RDBMS, on the other hand, is designed for content-based search.
to retrieve a record based on the value of any of its fields. This Historically, RDBMS have been the data manager of choice for enterprise applications, and they were designed for the enterprise data center environment. They demand large powerful machines, and frequent attention from database administrators.
predecessors. Focusing on the subset of SQL most suited to device datatypes like text and spatial, an embedded RDBMS will fit into a Megabyte of RAM or even less at run time.
For the first time, it is possible to think of embedding a relational database management system into a device application, and simple search interface to data.
In SQL, the application finds data by means of its content, not its location. An RDBMS stores data in tables made up of rows and columns. Rows are retrieved because the content of For example, information about music albums could be stored in a An RDBMS enables you to integrate data from many tables using a join.
A values. This is useful for a couple of reasons.
tables, perhaps by different applications.
Second is that you can and then cross-referencing it where it is needed.
In the example table above, we can see that the artist name is stored many times, once for each of their albums. We can eliminate this redundancy by separating the artists out into a table of their own.
We any data stored in a database, merely by specifying that field contents Central to maintaining data integrity is the idea of transactions. In an RDBMS, a transaction is a collection of statements that either execute completely or not at all. The classical transaction is a transfer between a checking and savings account.
Both the debit and the credit should happen, or neither should happen. There should never be a is Atomic, Consistent, Isolated and Durable.
a negative balance, and negative balances are illegal, then the transaction will not take place.
Transactions are Isolated so that seeing partial results midway through transaction execution, and they Even in a single-user, or single application environment, of actions or a media error. But they are essential in the more complex controlled access to shared data is a complicated business. Database engineers who specialize in this arcane branch of computing science.
Now that small footprint, self-managing RDBMS are available, it build data management logic from scratch. Once developers are relieved of the need to attend to the fine points of data management, they can focus on delivering the features that win customers. The result is a more robust, richer application delivered to market faster.
And in today's competitive markets there are few second prizes. Getting to The enterprise RDBMS was created to run back office business, and so it is heavily focused on support for alphanumeric data. But embedded search.
Some modern embedded RDBMS provide extensions to support these datatypes, bringing to them the same high level query interface that Each of these datatypes requires a new kind of index. Alphanumerics are scalar data: they can be distributed along a line. The B-tree search along this line.
Spatial data is 2- or 3-dimensional and cannot be efficiently searched using B-trees. Thus, a B-tree powered DBMS that lie within this circle." The spatial search engines that power sites like Yahoo Maps use special purpose search algorithms, not efficient search of spatial data.
Because of the ability of an RDBMS to integrate data from multiple tables, direct support for spatial data the database. It becomes easy to ask questions like, "Show me the names or some other location technology, new opportunities are arising to and its surrounding environment. These applications may even be able to operate when the device is disconnected from the network, supporting emergency services, or field workers in distant locations.
media content. With devices like MP3 players and Personal Video Recorders (PVRs) storing thousands of items of content, the classical folder-based interface breaks down.
Users need a more intuitive way to find desirable content.
One key is quantitative tagging. Content is tagged (by the user, or the content provider, or a community of users) using a number of quantitative metrics.
In the case of movies, this could be the complexity of the plot, or how scary the movie is, what ages it is suitable for, etc.
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