The Experts below are selected from a list of 6 Experts worldwide ranked by ideXlab platform
Randall Weis - One of the best experts on this subject based on the ideXlab platform.
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The Basic Scenario
Managing Time in Relational Databases, 2010Co-Authors: Tom Johnston, Randall WeisAbstract:When an object is represented by a row in a nonTemporal table, the sequence of events begins with the insertion of that row, continues with zero or more updates, and either continues on with no further activity, or ends when the row is eventually Deleted. When an object is represented in an asserted version table, the result includes one row corresponding to the insert in the nonTemporal table, additional rows corresponding to the updates to the original row in the nonTemporal table, and an additional row if a Delete eventually takes place. This sequence of events constitutes what is called the basic scenario of activity against both conventional and asserted version tables. This chapter describes how the basic scenario works when the target of that activity is an asserted version table. Basic Temporal transactions are Temporal transactions that do not specify any biTemporal parameters. Any one or more of three biTemporal parameters—an assertion begin date, an effective begin date or an effective end date—may be specified on a Temporal transaction. On a basic Temporal transaction, none of them are specified. A Temporal Delete is translated into a set of physical update transactions that withdraw the affected versions, followed by either one or two physical insert transactions that delimit the scope of the Delete and, if necessary, any number of withdrawals and replacements to adjust episode begin dates that may have been affected.
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Temporal Transactions on Multiple Tables
Managing Time in Relational Databases, 2010Co-Authors: Tom Johnston, Randall WeisAbstract:This chapter examines scenarios that modify multiple asserted version tables, and that involve Temporal referential integrity (TRI) and its enforcement. TRI is referential integrity applied to the Temporalized representations of objects by two types of managed objects—episodes and versions. A TRI relationship between a child managed object and a parent managed object is based on an existence dependency between the objects which those managed objects represent. In either an RI or a TRI relationship between a managed object representing a policy and one representing a client, a client may exist without a related policy, but a policy cannot exist without a related client. When TRI is concerned, “mays” and “cannots” are enforced on the managed objects that are versions and episodes, by the AVF, in accordance with rules declared to it as entries in metadata tables. A TRI child table is an asserted version table that contains a Temporal foreign key (TFK). A TRI parent table is an asserted version table referenced by a TFK. The foreign key (FK) reference is a data value, and is unambiguous; but the TFK reference, as a data value, is not unambiguous. The chapter explains how TRI can be applied to Temporal transactions including Temporal insert, Temporal updates, and Temporal Delete.
Tom Johnston - One of the best experts on this subject based on the ideXlab platform.
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The Basic Scenario
Managing Time in Relational Databases, 2010Co-Authors: Tom Johnston, Randall WeisAbstract:When an object is represented by a row in a nonTemporal table, the sequence of events begins with the insertion of that row, continues with zero or more updates, and either continues on with no further activity, or ends when the row is eventually Deleted. When an object is represented in an asserted version table, the result includes one row corresponding to the insert in the nonTemporal table, additional rows corresponding to the updates to the original row in the nonTemporal table, and an additional row if a Delete eventually takes place. This sequence of events constitutes what is called the basic scenario of activity against both conventional and asserted version tables. This chapter describes how the basic scenario works when the target of that activity is an asserted version table. Basic Temporal transactions are Temporal transactions that do not specify any biTemporal parameters. Any one or more of three biTemporal parameters—an assertion begin date, an effective begin date or an effective end date—may be specified on a Temporal transaction. On a basic Temporal transaction, none of them are specified. A Temporal Delete is translated into a set of physical update transactions that withdraw the affected versions, followed by either one or two physical insert transactions that delimit the scope of the Delete and, if necessary, any number of withdrawals and replacements to adjust episode begin dates that may have been affected.
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Temporal Transactions on Multiple Tables
Managing Time in Relational Databases, 2010Co-Authors: Tom Johnston, Randall WeisAbstract:This chapter examines scenarios that modify multiple asserted version tables, and that involve Temporal referential integrity (TRI) and its enforcement. TRI is referential integrity applied to the Temporalized representations of objects by two types of managed objects—episodes and versions. A TRI relationship between a child managed object and a parent managed object is based on an existence dependency between the objects which those managed objects represent. In either an RI or a TRI relationship between a managed object representing a policy and one representing a client, a client may exist without a related policy, but a policy cannot exist without a related client. When TRI is concerned, “mays” and “cannots” are enforced on the managed objects that are versions and episodes, by the AVF, in accordance with rules declared to it as entries in metadata tables. A TRI child table is an asserted version table that contains a Temporal foreign key (TFK). A TRI parent table is an asserted version table referenced by a TFK. The foreign key (FK) reference is a data value, and is unambiguous; but the TFK reference, as a data value, is not unambiguous. The chapter explains how TRI can be applied to Temporal transactions including Temporal insert, Temporal updates, and Temporal Delete.
