A segment has 3 occurrences for a parent. This segment is called a
-
multiple
-
twin
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sibling
-
none of these
In IMS hierarchical databases, when a segment type has multiple occurrences (instances) under the same parent segment, those occurrences are called 'twins'. Each twin represents a different record of the same segment type sharing a common parent. 'Sibling' refers to different segment types under the same parent, not multiple occurrences of the same type.
To answer this question, let's go through each option to understand why it is correct or incorrect:
Option A) Multiple - This option is incorrect because the term "multiple" is not used to describe a segment with 3 occurrences for a parent.
Option B) Twin - This option is correct because the term "twin" is used to describe a segment with 3 occurrences for a parent. In genetics, twins refer to two offspring produced from the same pregnancy. In the context of segments, a twin segment refers to a segment that occurs three times for a parent.
Option C) Sibling - This option is incorrect because the term "sibling" is not used to describe a segment with 3 occurrences for a parent. In genetics, siblings refer to individuals who share at least one common parent.
Option D) None of these - This option is incorrect because option B, "twin," is the correct answer.
The correct answer is B) Twin. This option is correct because it accurately describes a segment with 3 occurrences for a parent.