what is metadata repository in data warehouse
In this tutorial provide an Introduction and what is metadata repository in data warehouse.
Meta Data Repository:
Metadata is data about data. When used in a data warehouse, metadata
are the data that define warehouse objects. Metadata are created for the data
names and definitions of the given warehouse. Additional metadata are created
and captured for timestamping any extracted data, the source of the extracted
data, and missing fields that have been added by data cleaning or integration
processes.
A metadata repository should contain the following metadata repository in data warehouse:
•A description of the structure of the data warehouse, which includes
the warehouse schema, view, dimensions, hierarchies, and derived data
definitions, as well as data mart locations and contents.
Operational metadata, which
include data lineage (history of migrated data and the sequence of
transformations applied to it), the currency of data (active, archived, or purged),
and monitoring information (warehouse usage statistics, error reports, and
audit trails).
The algorithms used for summarization, which include measure and
dimension definition algorithms, data on granularity, partitions, subject areas,
aggregation, summarization, and predefined queries and reports.from the
The mapping from the operational environment to the data warehouse,
which includes source databases and their contents, gateway descriptions, data
partitions, data extraction, cleaning, transformation rules, and defaults, data
refresh and purging rules, and security (user authorization and access control).
Data related to system performance, which include indices and profiles
that improve data access and retrieval performance, in addition to rules for the
timing and scheduling of refresh, update, and replication cycles.are the
Business metadata, which includes business terms, definitions, and data
definition ownership information, and charging policies. are
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