segment

In the Oracle RDBMS, a segment is a logical data structure constructed out of extents. The four segment types are:

• Data segments are associated with (non-clustered) tables and contains the data stored within that table (or within a table partition)
• Index segments contain the data that the index is made up of
• Rollback segments contain undo information that is used in many very important ways, such as to ensure read-consistant views of data (for example, to implement an ACID transaction)
• Temporary segments store temporary data, to sort output, for example.

Segments are the largest of three data allocation structures in Oracle. Segments are constructed from extents, and extents are constructed from data blocks.

segment /seg'ment/ vi.

To experience a segmentation fault. Confusingly, this is often pronounced more like the noun `segment' than like mainstream v. segment; this is because it is actually a noun shorthand that has been verbed.

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.

In assembly programming, a segment is an relocatable code/data chunk.

Most assemblers have the distinction of code and data segments. In UNIX, the segments in object files are called text (for program code), data (for initialized data) and bss (for uninitialized data).

Seg"ment (?), n. [L. segmentum, fr. secare to cut, cut off: cf. F. segment. See Saw a cutting instrument.]

1.

One of the parts into which any body naturally separates or is divided; a part divided or cut off; a section; a portion; as, a segment of an orange; a segment of a compound or divided leaf.

2. Geom.

A part cut off from a figure by a line or plane; especially, that part of a circle contained between a chord and an arc of that circle, or so much of the circle as is cut off by the chord; as, the segment acb in the Illustration.

3. Mach. (a)

A piece in the form of the sector of a circle, or part of a ring; as, the segment of a sectional fly wheel or flywheel rim.

A segment gear.

4. Biol. (a)

One of the cells or division formed by segmentation, as in egg cleavage or in fissiparous cell formation.

One of the divisions, rings, or joints into which many animal bodies are divided; a somite; a metamere; a somatome.

Segment gear, a piece for receiving or communicating reciprocating motion from or to a cogwheel, consisting of a sector of a circular gear, or ring, having cogs on the periphery, or face. -- Segment of a line, the part of a line contained between two points on it. -- Segment of a sphere, the part of a sphere cut off by a plane, or included between two parallel planes. -- Ventral segment. Acoustics See Loor, n., 5.

© Webster 1913.

Seg"ment (?), v. i. Biol.

To divide or separate into parts in growth; to undergo segmentation, or cleavage, as in the segmentation of the ovum.

© Webster 1913.