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Questions tagged [unique-key]

A key is a set of attributes that is irreducibly unique and non-nullable within a table.

A key is a set of attributes that is irreducibly unique and non-nullable within a table. Irreducible means that all the attributes of the key are necessary to guarantee uniqueness - remove any one attribute and the uniqueness property would be lost. A key may consist of zero, one or more attributes and a relational table (relation variable) must have at least one key and may have more than one.

Keys are unique by definition so the commonly used term "unique key" is actually a tautology.

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Why identifierForVendor Is not return unique UUID

In swift, app we want unique device id.but will not get the unique UUID if i reinstall the same app. Here's how we get UUID: if let uuid = UIDevice.current.identifierForVendor?.uuidString { print(uuid) }
Shantaram Kokate
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python unique id generation

I want to generate a unique id which will have 10 characters. These will include 32 characters/numerics I.e 'a' to 'v' and '0' to '9'. Adjacently repeated characters are disallowed for e.g '1hdhusiit' in this 'ii' is adjacent. Each key should be…
uroosa
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Generate Unique Employee code in String

I am implementing Employee Management System in Java. I want employee code to be auto generated on new employee registration and I should be in predefined format. I don't want to use auto incremented integer key as a employee ID. I am using MySQL…
Nilesh Deshmukh
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how to make fields of arraylist unique?

class Employee implements Comparable { public Employee(int id, String name,int salary ,String designation) {..} //getters and setters } public class TestEmployeeSort { public static void main(String[] args) { …
ravindersangwan
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Unique IDs using PHP

Can any one tell me how can I create unique ID? For example: Account id 9845673333 Account id 9845673334 Account id 9845673335 Account id 9845673336
Rashpal
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