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28 sie 2024 · An alternate key (also known as secondary key) is a column or a combination of columns in a table that can uniquely identify each row, but is not the primary key. In other words, it is an alternative to the primary key that could have been chosen as the primary key but wasn’t.
26 lip 2022 · These are basically secondary Candidate Keys that can uniquely identify a row in a table. So, Alternate Keys are also sometimes known as “Secondary Keys”. In other words, we can define the Alternate key as the set of Candidate Keys other than the Primary Key.
When a query is performed on a table that has an alternate key, the DBMS uses the alternate keys to help locate the relevant records. The alternate key is indexed in much the same way as a primary key, allowing for efficient lookup and retrieval of data.
SQL Alternate Keys in a database table are candidate keys that are not currently selected as a primary key. They can be used to uniquely identify a tuple (or a record) in a table.
25 lip 2024 · In MySQL, an alternate key is a column or set of columns that can uniquely identify a record, similar to a primary key, but isn’t chosen as the primary key. Alternate keys ensure data uniqueness and provide additional ways to access records.
20 sie 2019 · Candidate keys are SID or FNAME+LAME. Primary Key: SID. Alternate Key: FNAME+LAME. now with some explanation. Candidate Keys are those keys which is candidate for primary key of a table. simply all columns which full fill all the requirements of primary key.
The alternate key is useful in providing an additional way of uniquely identifying the rows in a table. In this tutorial, we learned about the alternate key in SQL, its syntax, an example of creating an alternate key, its output, explanation, use, important points, and a summary.
