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ENV510 Landscape Ecology and GIS
Definitions
& descriptions | Concepts
& issues | Setting
up GIS | Using
GIS
| Applications
Representation
| Spatial data | Referencing
| Data issues
| Accuracy
| Error
| Management
| File systems | DBMS
| Hierarchical
| Network
| Relational | OO
This type
of approach has no pointers and no hierarchy, instead the data are stored in
simple records known as tuples.
Tuples are sets of fields which each contain an attribute.
Tuples
are grouped together in tables known as relations.
Each table or relation is usually a separate file.
Data are extracted from a relational database by the user defining the relation that is appropriate to the query. Structured query language (SQL) is commonly used to query the database.
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