In a recent phone interview, Editor-in-Chief Joe Francica discussed how Bentley was working with both ESRI and Oracle to help their customers better manage spatial data.Bentley Vice President, Styli Camateros, provides his opinions about working with both ESRI's ArcSDE and Oracle's Spatial technology, and what he recommends to Bentley's customers.
J.Francica (JF): Styli, can you provide some background on the technology of the ArcSDE Connector or Oracle Connector and what are the technological hurdles of working with an essentially flat file system and connecting that to a relational database?
Styli Camateros (SC): First, the DGN is not a flat file anymore.With the DGN file (format) in V8 (MicroStation Version 8), you can incorporate a schema; meaning that you can 'hang off' attributes and rules and all kinds of things in XML in a DGN element.So, you can actually define a schema on which you can hang data and it is preserved in the DGN file itself.So, XML becomes a way of persisting and transforming and defining that data.What we've done in geospatial with what we call XFM, really makes that richer.So, XFM is an acronym for XML-based Feature Modeling.And essentially we give you an interface, called a geospatial administrator, to allow you to define a schema.So, features and the attributes and the business objects that you want to hang off of that (feature), and the rules of how you are going to place that feature, plus any domain constraints that you want to have for that feature, can be defined in this geospatial administrator.And then when you use MicroStation GeoGraphics, you can place these things and all the rules behave the way they should.So, you pick a road or start to place a road feature, and it will prompt you to capture the attributes and we'll make sure that your domain constraints are conserved.
JF: So, the descriptor of an attribute is entered before you start capturing data?
SC: What happens is that the schema definition is instantiated when you open the session.So, even if you don't have anything in your DGN file, when you use Geographics we reserve part of that to put all that stuff in there.
So, you have a DGN file that has graphics, and the graphics have all those attribute associated with them; they have domain constraints associated to them; they have relationships.So, in a sense, if I want property-based associations, I can actually create that in the DGN file. So, we have all those relationships: we have the graphics; we have the attributes; we have the relationships; we have the domain constraints. So, the Connectors take all that information and put it in Oracle or Oracle Spatial or put it in ArcSDE.
We also have tools that can search across many DGN files.So, we can also answer the question, Where are all the manholes?
So, in answer to your question, it depends on your preference.The caveat is that there are some things that you can put in a DGN that you can't put in a database.For example, if you are doing asymmetric vertical curves, well, you can't put that in ArcSDE and you can't put that in Oracle.You might have a preference to use engineering-based applications, because there are some limits in the database.But if you choose to put everything in the database, then we can support you with doing that too.If at the end of the day you want to do some work in MicroStation and put all that information in ArcSDE, we'll generalize that information that can't be transported.And, you have control of the information that ends up in SDE; and the same thing with Oracle.
It all depends on what you need and what tools you like to use or what features you really need.Do you really need to have one central database and everything in it or do you want to do federated data management?
From our point of view, we essentially give you the choice to go back and forth from your applications.
JF: And what if someone wants to build topology? Is your fallback position to use Oracle Spatial?
SC: We do support topology, or we will in the XFM edition, inside of Geographics. XFM supports topology, so we have all the rules and it will be exactly like Oracle V8.
JF: Are you finding that ArcSDE or Oracle is easier to work with?
SC: We have very good customers who have a large part of their operations based on ArcSDE.And we want to support that.We have many customers that want Oracle to be their central GIS database, and we want to support that.Now, if you ask me over the long term what do we encourage, especially topology for example, I think that's going to be an IT (information technology) function.And over time, I think, Oracle is going to be hard to resist. But that's my opinion.
JF: But, you are saying that from a global data management perspective.So is it your opinion that Oracle is providing the better tools?
SC: I think so and frankly, if you look ten years from now, and ten years is a long time, why wouldn't every cadastre base their applications on the topology model in Oracle Spatial?
JF: Are you seeing more customers gravitate to a relational database system like Oracle or DB2? And are you seeing customers relegate spatial data to a centralized, IT data store?
SC: Yes.I think one of the things is that maybe people are hesitant now about proprietary systems, but I'm not absolutely sure that's true yet.But they look to Oracle as "hey, if I have my data in there and it behaves properly, I can always get at it any way I want," because its kind of a universal way of taking data.And I think they are looking at it as the really good thing about Oracle Spatial.
JF: Are your also seeing that the concept of an enterprise GIS is being better facilitated by the availability of spatial data in a central database?
SC: Certainly having spatial data exposed in a database is something people want.It goes back to what you can put in a database and what can't you.I think a lot of what you have can't be put in a database in any constructive way.So, if you want GIS data and you want it shared, a good place to put it is in Oracle.Of course, we understand that you have all kinds of other data, but we'd like to offer you a federated environment so that you can find all this stuff, including what's in an Oracle GIS.So, if you go back to the Google analogy, in a sense that, Google is very distributed but they've indexed them (the information) and when you ask a question you get an answer.So, if you want to create a GIS database, Oracle is a good place to put data, and don't worry about getting all your other information in there because we'll give you the tools to integrate the two.
JF: And that's how you are positioning ProjectWise?
SC: Absolutely.ProjectWise's job is that.
JF: If some company was just starting out with their project, what are you recommending?
SC: If somebody had nothing, and they don't care about changing, I would probably recommend Oracle.
JF: Thanks, Styli.This have been a very useful discussion.