When you create a database, SAP ASE creates three segments in the database.
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system – stores the database’s system tables.
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logsegment – stores the database’s transaction log.
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default – stores all other database objects—unless you create additional segments and store tables or indexes on the new segments by using create table...on segment_name or create index...on segment_name.
If you create a database on a single database device, the system, default, and logsegment segments are created on the same device. If you use the log on clause to place the transaction log on a separate device, the segments resemble those shown below:
Although you can add and drop user-defined segments, you cannot drop the default, system, or log segments from a database. A database must have at least one of each type of system-defined segment: system, logsegment, and default.
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sp_addsegment – defines a segment in a database.
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create table and create index – creates a database object on a segment.
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sp_dropsegment – removes a segment from a database or removes a single device from the scope of a segment.
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sp_extendsegment – adds devices to an existing segment.
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sp_placeobject – assigns future space allocations for a table or an index partition to a specific segmen.t
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sp_helpsegment – displays the segment allocation for a database or data on a particular segment.
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sp_helpdb – displays the segments on each database device.
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sp_help – displays information about a table, including the segment where the table resides.
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sp_helpindex – displays information about a table’s indexes, including the segments where the indexes reside.