Gap detection in a temporally unique index in a relational database

摘要

Methods for gap detection in a temporally unique index in a relational database. A temporally unique index is provided in a relational database. The index includes a first set of keys, each including one or more non-temporal and two temporal key parts. In response to receiving an insert, update, or delete statement for a changed row, the rows with identical non-temporal key parts to the changed row are identified. The temporal key parts of the identified rows are compared to the temporal key parts of the changed row to determine whether: the changed row is directly adjacent to a temporally earlier row and temporally later row, a gap is detected between the changed row and a temporally earlier row, or a gap is detected between the changed row and a temporally later row.

主权项

1. A method for gap detection in a temporally unique index in a relational database, comprising:
providing a temporally unique index in a relational database, wherein the temporally unique index includes a first set of keys, wherein each key in the first set of keys includes one or more non-temporal key parts and two temporal key parts indicating a temporal beginning value and a temporal end value; and in response to receiving one of an insert statement, an update statement, and a delete statement pertaining to a changed row in the relational database,
identifying rows in the temporally unique index that have identical non-temporal key parts to the changed row, andcomparing the temporal key parts of the identified rows to the temporal key parts of the changed row to determine: whether the changed row is directly adjacent to both a temporally earlier row and to a temporally later row, whether a gap is detected between the changed row and a temporally earlier row, or whether a gap is detected between the changed row and a temporally later row.