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Spatial Data Type Definitions in ORDB Abstract Data Types (ADT)

Spatial Data Type Definitions in ORDB Abstract Data Types (ADT). Defining Spatial Data Types in SQL3. SQL3 User defined data type -Overview CREATE TYPE statements Defines a new data types Attributes and methods are defined Separate statements for interface and implementation

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Spatial Data Type Definitions in ORDB Abstract Data Types (ADT)

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  1. Spatial Data Type Definitions in ORDB Abstract Data Types (ADT)

  2. Defining Spatial Data Types in SQL3 • SQL3 User defined data type -Overview • CREATE TYPE statements • Defines a new data types • Attributes and methods are defined • Separate statements for interface and implementation • Additional effort is needed at physical data model level

  3. Semantics • For point data type an important operation is Distance • Length operation is not a semantically correct operation on a Point • In relational databases the set of data types is fixed • In object-relational and object-oriented databases, this limitation has been relaxed • And there is built in support for user-defined data types.

  4. ADT definition in SQL3/SQL99 • Colons before u and v signify them as local variables. • Remember, ADT is like classes in object oriented technology. It can have attributes & member functions (eg. to modify values etc.) • To instantiate, create a table:

  5. Row Type definition in SQL3/SQL99 • CREATE ROW TYPE Point ( x NUMBER, y NUMBER, ); Colons before u and v signify them as local variables

  6. Write an Object Relational Scheme for Logical Model • 3 Relations • Country(Name, Cont, Pop, GDP, Life-Exp, Shape) • City(Name, Country, Pop,Capital, Shape) • River(Name, Origin, Length, Shape)

  7. River Representation Oracle syntax

  8. Country Representation

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