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elwoos
Master Smack Fu Yak Hacker
2052 Posts |
 Posted - 2009-06-01 : 10:05:33
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We are looking at implementing some spatial databases some of which will be on SQL Server 2008 which I am not (yet) familiar with (am I allowed to say that here  ). As a result there has been some (suprisingly) passionate debate about the role of a dba with regards to spatial databases. As a result I have some questions and would be interested in any thoughts1) Are you a dba for any spatial databases?2) If so, do you require any specialist knowledge for dealing with spatial datatypes, in particular do you have/need any knowledge of spatial data?I suspect I know the answers to these but I am a little biased.thanks in advancesteve-----------ASCII and ye shall receive. |
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spirit1
Cybernetic Yak Master
11752 Posts |
Posted - 2009-06-01 : 10:20:58
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| 1) no, not really.2) in sql 2008 you get new spatial datatypes geometry and geography. you should get familiar with them and their indexing structure. it's an R-Tree transformed into a B-tree.they make distance calculations really easy.___________________________________________________________________________Causing trouble since 1980Blog: http://weblogs.sqlteam.com/mladenpSpeed up SSMS development: www.ssmstoolspack.com <- version 1.5 out! |
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elwoos
Master Smack Fu Yak Hacker
2052 Posts |
Posted - 2009-06-02 : 07:07:02
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| Am I right in saying that it's the structure of the data you need to understand though not neccessarily the actual data itself. I can see that the indexing for them may be different to other datatypes but again that is more about the structure than the data itself isn't it? As I understand it most of the geospatial objects are sequences of connected lines (which I use to include single points and polygons which may or may not be closed) - do I really need to know much more than that about the data?thankssteve-----------ASCII and ye shall receive. |
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SwePeso
Patron Saint of Lost Yaks
30421 Posts |
Posted - 2009-06-02 : 08:28:14
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The Spatial data is stored as binary(128).The .Net implements this and transforms into GeoXXX datatype from .Net library.
E 12°55'05.63"N 56°04'39.26" |
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elwoos
Master Smack Fu Yak Hacker
2052 Posts |
Posted - 2009-06-03 : 04:19:31
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| Thanks Peso.steve-----------ASCII and ye shall receive. |
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SwePeso
Patron Saint of Lost Yaks
30421 Posts |
Posted - 2009-06-03 : 05:21:30
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My point is that it is easier to use the new datatypes because of the built-in methods on the datatypes, but there is an overhead of using them.An alternative is to store the coordinates as DECIMAL(9, 6) and use the distance formulas (most by MVJ) in the Library forum.Takes less space and is somewhat faster than invoking .net methods.
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Spatially challenged