Object representation of relational database cells having nontraditional large object datatypes
First Claim
1. In a computer system having a database under control of a server-based database management system which supports a large object (LOB) datatype, said database including a table with rows and columns, cells being defined by intersections of said rows and said columns, one of said rows having a cell of said LOB datatype, a data access method for a client-based applications program to access and manipulate a LOB value of said cell, said method comprising the steps of:
- providing to said applications program an object representing said cell, said object having member functions including functions for;
setting a LOB access mode of said object to a direct method, andsetting said LOB access mode to an indirect method;
wherein;
when said direct method is set, said object responds to a retrieval request of said applications program by causing said database management system to provide to said object said LOB value, said manipulation of said LOB value occurring at said client by said object;
when said indirect method is set, said object responds to said retrieval request by causing said database management system to provide a LOB locator usable by said database management system, said manipulation of said LOB value occurring at said server;
said applications program accesses and manipulates said LOB value by sending a message to said object.
1 Assignment
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Accused Products
Abstract
A program product is described in which a class library is provided to permit object oriented applications to access and to manipulate, in accordance with the object model, nontraditional data values of a relational table and, in particular, large objects. The data is manipulable by virtue of extended data objects that each represent a cell of a relational row, and that each inherit type-specific behaviors from the class library. Special handling for large objects is provided so as to avoid undue burdens on performance.
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Citations
18 Claims
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1. In a computer system having a database under control of a server-based database management system which supports a large object (LOB) datatype, said database including a table with rows and columns, cells being defined by intersections of said rows and said columns, one of said rows having a cell of said LOB datatype, a data access method for a client-based applications program to access and manipulate a LOB value of said cell, said method comprising the steps of:
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providing to said applications program an object representing said cell, said object having member functions including functions for; setting a LOB access mode of said object to a direct method, and setting said LOB access mode to an indirect method; wherein; when said direct method is set, said object responds to a retrieval request of said applications program by causing said database management system to provide to said object said LOB value, said manipulation of said LOB value occurring at said client by said object; when said indirect method is set, said object responds to said retrieval request by causing said database management system to provide a LOB locator usable by said database management system, said manipulation of said LOB value occurring at said server; said applications program accesses and manipulates said LOB value by sending a message to said object. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A computer system, comprising:
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a database, including a table with rows and columns, cells being defined by intersections of said rows and said columns, a server-based database management system controlling said database and supporting a large object (LOB) datatype, one of said rows having a cell of said LOB datatype, a data access facility interfacing with said database management system, and a client-based applications program for accessing and manipulating a LOB value of said cell; said applications program providing to said data access facility an access request pertaining to said cell; said data access facility providing to said applications program, in response to said access request, an object representing said cell, said object having member functions including functions for setting a LOB access mode of said object to a direct method, and for setting said LOB access mode to an indirect method; wherein when said direct method is set, said object responds to a retrieval request of said applications program by causing said database management system to provide to said object said LOB value, said manipulation of said LOB value occurring at said client by said object; wherein when said indirect method is set, said object responds to said retrieval request by causing said database management system to provide a LOB locator usable by said database management system, said manipulation of said LOB value occurring at said server; and wherein said applications program accesses and manipulates said LOB value by sending a message to said object. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A program product, comprising:
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a class library, and a computer-readable medium bearing said class library; said class library including a particular class for constructing an object to represent a selected cell in a computer system having a relational database supporting a large object (LOB) datatype, said selected cell having said LOB datatype, said relational database having a server location and said object having a client location; said particular class defining member functions of said object, including a function for setting a LOB access mode of said object to a direct method, a function for setting said LOB access mode to an indirect method, and a function for performing a retrieval with respect to said selected cell; said member functions of said object being defined by said particular class so that; when said direct method is set, said retrieval is performed by causing said database management system to provide to said object said LOB value so that manipulation of said LOB value may be performed at said client location; when said indirect method is set, said retrieval is performed by causing said database management system to provide to said object a LOB locator, said LOB locator being usable by said relational database so that manipulation of said LOB value may be performed at said server location. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification