Repository Table Types

The Waveset repository contains three types of tables, and each table has slightly different usage characteristics.

• Attribute Tables. These tables enable you to query for predefined single-valued or multi-valued object attributes.

  For most object types, stored attributes are hard-coded.

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  Note –

  The User and Role object types are exceptions to this rule. The inline attributes that are stored in the object table for User and Role are configurable, so you can configure additional custom attributes as queryable.

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  When you search for objects based on attribute conditions, Waveset accesses attribute tables in joins with the corresponding object tables. Some form of join (such as a JOIN, an EXISTS predicate, or a SUB-SELECT) occurs for each attribute condition.

  The number of rows in the attribute table are proportional to the number of rows in the corresponding object table. The values distribution might exhibit skew, where multi-valued attributes have a row per value and some objects might have more attributes or more attribute values than others. Typically, there is a many-to-one relation between rows in the attribute table and rows in the object table.

  Attribute tables have ATTR in the table name.

• Change Tables. Waveset uses a change table to track changes made to a corresponding object table. These table sizes are proportional to the rate of object change, but the tables are not expected to grow without bound. Waveset automatically truncates change tables.

  Change tables can be highly volatile because the lifetime of a row is relatively short and new rows can be created frequently.

  Access to a change table is typically performed by a range scan on the time-stamp field.

  Change tables have CHANGE in the table name.

• Object Tables. The Waveset repository uses object tables to hold serialized data objects, such as Large Objects (LOBs). Object tables can also hold commonly queried, single-valued object attributes.

  For most object types, stored attributes are hard-coded.

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  Note –

  The User and Role object types are exceptions to this rule. The inline attributes that are stored in the object table are configurable, and you can configure additional custom attributes as queryable for User and Role.

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  The number of rows in an object table equals the number of objects being stored. The number of objects stored in each object table depends on which object types are being stored in the table. Some object types are numerous, while other types are few.

  Generally, Waveset accesses an object table by object ID or name, though Waveset can also access the table by using one of the attributes stored in the table. Object IDs and names are unique across a single object type, but attribute values are not unique or evenly distributed. Some attributes have many values, while other attributes have relatively few values. In addition, several object types can expose the same attribute. An attribute may have many values for one object type and few values for another object type. The uneven distribution of values might cause an uneven distribution of index pages, which is a condition known as skew.

  Object tables are tables that do not have ATTR or CHANGE suffixes in the table name.