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Surrogate Keys are just a key number that will never appear in the real world, they are numbers automatically generated by systems to identify records. Surrogate keys lack a business significance unlike natural keys, which come from real-world data like email id or employee number or social security number. They are usually automatically generated, for example auto incrementing integers or sequence numbers. So the purpose of surrogate keys is to be able to uniquely identify rows in a table, even when business data changes! Data Engineering Course

Surrogate keys provide vital means to maintain data integrity and circumvent complexities in relationships among the data in present day database management systems (DBMS) including data warehouses. Natural keys might look like a good idea at first, but they can be pain in the rear. Characteristics of Business aspects can change, not unique across systems or are too big and complex to be used as primary keys. Surrogate keys address these points by providing a neutral identifying value that is stable during the life of a record.

One of the biggest points of using surrogate keys is the stability. Natural keys are according to the business rules and business rules change. For instance, a customer may change their email address or phone number, or a product code might have to be rearranged because of implementation of a new classification system. If those properties are put into the primary key, it results in relational integrity problems, or even the need of an extremely expensive cross-table update operation. A surrogate key, once assigned, never changes and this provides stability in database relationships over time.

Performance is another reason for using surrogate keys. Surrogate keys are a good old plain number, and indexes on numbers are much faster. These joins on numbers are much faster than a clumsy join through a large text-based natural key. This performance edge is of the essence for large systems dealing with millions or billions of records each day. Quicker joins and smaller indexes decrease the time of query execution and increase the scalability of the entire system. Jobs openings

Surrogate keys are increasingly important when database systems that employ dimension modeling (such as those commonly used in data warehousing) are being designed. In star and snowflake schemas associative fact tables refer dimension tables by surrogate keys. This is a method that enables the data warehouse to deal with historical changes. For instance, if a customer modifies their address, a new dimension record can be added with a new surrogate key, while the original will not be deleted. This allows proper historical reporting referred to as slowly changing dimensions, which is difficult to implement using only natural keys.

To paraphrase a friend of mine, data integration is one of the places where surrogate keys really earn their keep. Also, business units usually draw data from several source systems which use different ways of identifiers and formats. There may exist differing natural keys for the identical real-world entity in different systems. If you use a surrogate key in the target, then those to rows can be joined using that column. This simplifies data aggregation, reporting and analytics, with reduced reliance on source specific identifiers.

There are also only 20 available surrogate keys to help insure data quality or consistency. Unsurprisingly, natural keys could have errors, duplication and missing values; that's more likely if the source is a manual data entry system or outdated application. Dependent on fields such as a primary key will lead to the risks of integrity. As surrogate keys are system generated this reduces the likelihood of duplication, each record will have a valid unique identifier. As a result, the database constraints are easier to manage and more robust.

Surrogate keys offer additional power to schema design. Any changes to business attributes will not affect primary or foreign keys because surrogate keys are indifferent from business logic. It separates concerns and so code becomes easier to maintain and change as business rules changes. The flexibility of being able to respond to changing business situations as the company grows, expands and reshapes itself is important for minimizing technical debt, long-term maintenance etc.

But, surrogate keys are not without controversy and one must be clear about when they should be used. And so they should not entirely substitute natural keys, instead of that power them. Natural keys are no less significant on enforcing business rules and guarantee real world uniqueness. As a best practice you can use surrogate keys as primary key and enforce uniqueness on your natural (business) key via other constraints. It's a compromise between some of the advantages of surrogate keys and the business integrity they do not have.

Surrogate keys also have implications in governance and compliance, which can have an impact on achieving certain business objectives. By replacing these sensitive business identifiers they can also limit exposure of PII in one’s analytical systems. This is consistent with both good data ethics and regulatory needs. Responsible data management is an important aspect, in companies that are value driven: transparency, accountability and Corporate Social Responsibility. Employing surrogate keys may be part of a plan to hide sensitive data while continuing to conduct heavy analytics/reporting processing.

In conclusion, surrogate keys are machine-generated numbers used to uniquely and rapidly identify database and warehouse records. They are just used as they provide stability, performance benefit and integration mechanism and support history tracking (data). Surrogate keys abstracts system IDs and allows us to separate technical identifiers from business level before object storage in the systems. Although they should not be used carelessly in conjunction with natural keys, their advantages make them a required element of contemporary data design. Just looks like it will simply last until Monday, when data are massiely/ipenightly -ing whatever the system is we you have there It's kind of a one-day summary that uses something other than user input for its keys, allowing the user to limit them in useful ways as yet unimplemented.