Surrogate keys are unique identifiers used in data warehouses to replace primary keys from source systems. They protect against changes to source systems, allow integration from multiple sources, enable rows that do not exist in sources, track changes over time such as new customer records for address changes, replace text keys with more efficient integers, and provide higher performance than long alphanumeric keys.

1. DATA WAREHOUSING
Multi Dimensional
Data Modeling.
Surrogate Keys.

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4.  A surrogate key is a unique identifier for data
warehouse records that replaces source primary keys
(business/natural keys)
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5.  Protect against changes in source systems
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6.  Allow integration from multiple sources
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7.  Enable rows that do not exist in source data
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8.  Track changes over time (e.g. new customer instances
when addresses change)
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9.  Replace text keys with integers for efficiency
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10.  Higher performance with numeric keys than with
long, alphanumeric keys
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11.  The Data Warehouse Toolkit.Second
Edition.The Complete Guide to Dimensional
Modeling.Ralph Kimball.Margy Ross