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What is surrogate key and composite key?
A composite key is simply a key that contains two or more columns. A surrogate key is one which is not naturally unique to the data but is added or imposed onto the data for (hopefully) a good reason. Examples can include IDENTITY columns in SQL Server – known as autonumbers sometimes in other products.
What is the difference between a Simplekey and composite key?
Also of note is this factoid: A simple key is a key made up of one column, whereas a composite key is made up of two or more columns.
What is the difference between a composite value primary key a surrogate value primary key?
A table may have only one primary key, but it may be composite (consist of more than one column). A surrogate key is any column or set of columns that can be declared as the primary key instead of a “real” or natural key.
What’s the difference between a composite key and surrogate key?
A composite key is simply a key that contains two or more columns. A surrogate key is one which is not naturally unique to the data but is added or imposed onto the data for (hopefully) a good reason.
When to use identity column or surrogate key?
Using an identity column for tables that define entities is fair enough, but I’m not sure why you would use a surrogate key over a composite key for tables that relate entities. Firstly, it’s worth pointing out that an identity column is only a type of primary key.
When to use a surrogate or natural key?
A table that defines entities is one that describes a single entity within your problem domain, say a person or a product. In this case, a surrogate primary key may well be more appropriate than using the natural key as it is will not be vulnerable to any changes in the characteristics of the entities over time.
How is composite key used in Oracle EE?
The composite key is based on 2 surrogate keys and is a bulletproof way to ensure data integrity among clients and within the database a whole. After this you would create views (or if using Oracle EE setup Virtual Private Database) and other various structures to allow the database to enforce row level security (which is a topic all it own).