System and method for managing relational numerical data for monitoring systems
An object-oriented system for managing relational numerical data includes a relation interface that provides access to a relation and its attributes and tuples, where an attribute is a data item with a numeric value and a relation is a set of n-tuples of attribute values, where the relation interface maintains its tuples in a fixed order and is adapted to selecting subsets of attributes and/or tuples where a new relation interface instance is created, an iterator interface for iterating over the tuples of a relation, where the iterator is adapted to acquiring the tuple attribute data as data is being accessed, and a notification interface for notifying other classes whenever changes occur in a relation interface instance.
1. A computer-implemented object-oriented system for managing relational numerical data, comprising:
a relation interface that provides access to a relation and its attributes and tuples, wherein an attribute is a data item with a numeric value and a relation is a set of n-tuples of attribute values, wherein said relation interface maintains its tuples in a fixed order and selects subsets of attributes and/or tuples wherein a new relation interface instance is created; and
an iterator interface for iterating over the tuples of a relation, wherein said iterator acquires the tuple attribute data as said data is being accessed.
2. The system of claim 1 , further comprising:
a tuple interface for providing access to tuple values for each attribute of a relation, wherein each tuple interface instance is associated with a particular relation interface instance, and
wherein said iterator interface extends said tuple interface and saves and restores a current position in the tuples of said relation, moves to a tuple position defined by an attribute value, determines whether an iterator's current position corresponds to one of a relation's tuples and whether a current tuple is the first tuple in a continuous segment of tuples within the relation.
3. The system of claim 1 , further comprising:
an attribute interface that represents an attribute of a relation and provides access to said attribute's identifier, numeric data type, meta-data, range of values assumed by said attribute in said relation, value status and actual value of said attribute, wherein each attribute interface instance is associated with a relation interface instance.
4. The method of claim 3 , wherein said meta-data of an attribute includes a textual description of said attribute, the measurement used for the attribute's values, and allowable range of values for the attribute.
5. The system of claim 1 , wherein said relation interface selects a subset of attributes to identify tuples in a relation.
6. The system of claim 1 , further comprising an identifier interface that represents an identifier for attributes that can be used across multiple relations, wherein an attribute common to a plurality of relations is identified by a single name.
7. The system of claim 1 , further comprising a condition interface for evaluating one or more attribute conditional expressions for selecting attributes for a tuple.
8. The system of claim 1 , wherein said relation represents a plurality of time based sensor measurements, wherein each attribute is associated with measurements from one sensor, and each attribute value is associated with a time stamp.
9. The system of claim 8 , further comprising a source layer that acquires attribute data from one or more data sources as a time series of measurements with associated timelines and sorts the measurements for each attribute; and
a processing layer that merges timelines for each of the measurement time series into a single merged timeline, makes the measurement data available to an application program, and that includes a cache for storing data acquired from the source layer.
10. The system of claim 9 , wherein said cache, when an application requests measurement data in a specified time range with a start time and an end time, determines whether a data cluster stored in said cache covers said time range, and if so, returns said cluster to said application, wherein if a cluster does not cover the requested time range, determines the start time of a new time range from a cluster stored in said cache, wherein if said new start time is before the requested end time, said cache returns data in the range of said requested start time and said new start time, and wherein if said new start time is after the requested end time, said cache returns data in the range of said requested start time and said requested end time.
11. The system of claim 9 , wherein said processing layer merges timelines by associating an index variable with each attribute that corresponds with its timestamp in the merged timeline, comparing timestamps of all attributes at a position indicated by said index variable to find a next timestamp, and adding the next timestamp to the merged timeline.
12. The system of claim 1 , wherein said relation represents a bitmap color image using red, green, and blue color values, wherein each pixel of said bitmap image is associated with an attribute for each of its coordinates and each of its color values.
13. A computer-implemented object-oriented system for managing relational numerical data, comprising:
a relation interface that provides access to a relation and its attributes and tuples, wherein an attribute is a data item with a numeric value and a relation is a set of n-tuples of attribute values, wherein said relation interface maintains its tuples in a fixed order and selects subsets of attributes and/or tuples wherein a new relation interface instance is created;
a tuple interface for providing access to tuple values for each attribute of a relation, wherein each tuple interface instance is associated with a particular relation interface instance, and
an attribute interface that represents an attribute of a relation provides access to said attribute's identifier, numeric data type, meta-data, range of values assumed by said attribute in said relation, value status and actual value of said attribute, wherein each attribute interface instance is associated with a relation interface instance.
14. The system of claim 13 , further comprising an iterator interface for iterating over the tuples of a relation, wherein said iterator acquires the tuple attribute data as said data is being accessed, wherein said iterator interface extends said tuple interface, saves and restores a current position in the tuples of said relation, moves to a tuple position defined by an attribute value, determines whether an iterator's current position corresponds to one of a relation's tuples and whether a current tuple is the first tuple in a continuous segment of tuples within the relation.
15. A program storage device readable by a computer, tangibly embodying a program of instructions executable by the computer to implement an object-oriented system for managing relational numerical data, said system comprising:
a relation interface that provides access to a relation and its attributes and tuples, wherein an attribute is a data item with a numeric value and a relation is a set of n-tuples of attribute values, wherein said relation interface maintains its tuples in a fixed order and selects subsets of attributes and/or tuples wherein a new relation interface instance is created; and
an iterator interface for iterating over the tuples of a relation, wherein said iterator acquires the tuple attribute data as said data is being accessed.
16. The computer readable program storage device of claim 15 , said system further comprising:
a tuple interface for providing access to tuple values for each attribute of a relation, wherein each tuple interface instance is associated with a particular relation interface instance, and
wherein said iterator interface extends said tuple interface, saves and restores a current position in the tuples of said relation, moves to a tuple position defined by an attribute value, determines whether an iterator's current position corresponds to one of a relation's tuples and whether a current tuple is the first tuple in a continuous segment of tuples within the relation.
17. The computer readable program storage device of claim 15 , said system further comprising:
an attribute interface that represents an attribute of a relation and provides access to said attribute's identifier, numeric data type, meta-data, range of values assumed by said attribute in said relation, value status and actual value of said attribute, wherein each attribute interface instance is associated with a relation interface instance.
18. The computer readable program storage device of claim 17 , wherein said meta-data of an attribute includes a textual description of said attribute, the measurement used for the attribute's values, and allowable range of values for the attribute.
19. The computer readable program storage device of claim 15 , wherein said relation interface selects a subset of attributes to identify tuples in a relation.
20. The computer readable program storage device of claim 15 , said system further comprising an identifier interface that represents an identifier for attributes that can be used across multiple relations, wherein an attribute common to a plurality of relations is identified by a single name.
21. The computer readable program storage device of claim 15 , said system further comprising a condition interface for evaluating one or more attribute conditional expressions for selecting attributes for a tuple.
22. The computer readable program storage device of claim 15 , wherein said relation represents a plurality of time based sensor measurements, wherein each attribute is associated with measurements from one sensor, and each attribute value is associated with a time stamp.
23. The computer readable program storage device of claim 22 , said system further comprising a source layer that acquires attribute data from one or more data sources as a time series of measurements with associated timelines and sorts the measurements for each attribute; and
a processing layer that merges timelines for each of the measurement time series into a single merged timeline, makes the measurement data available to an application program, and that includes a cache for storing data acquired from the source layer.
24. The computer readable program storage device of claim 23 , wherein said cache, when an application requests measurement data in a specified time range with a start time and an end time, determines whether a data cluster stored in said cache covers said time range, and if so, returns said cluster to said application, wherein if a cluster does not cover the requested time range, determines the start time of a new time range from a cluster stored in said cache, wherein if said new start time is before the requested end time, said cache returns data in the range of said requested start time and said new start time, and wherein if said new start time is after the requested end time, said cache returns data in the range of said requested start time and said requested end time.
25. The computer readable program storage device of claim 23 , wherein said processing layer merges timelines by associating an index variable with each attribute that corresponds with its timestamp in the merged timeline, comparing timestamps of all attributes at a position indicated by said index variable to find a next timestamp, and adding the next timestamp to the merged timeline.
26. The computer readable program storage device of claim 15 , wherein said relation represents a bitmap color image using red, green, and blue color values, wherein each pixel of said bitmap image is associated with an attribute for each of its coordinates and each of its color values.