Top "Unique-key" questions

how to generate unique id in php based on current data and time?

I need to generate a unique ID in php based on current date and time to keep a log of …

php date datetime time unique-key

MySql - Is primary key unique by default?

If I define a column as a primary key in MySql, is it also unique key by default or do …

mysql primary-key unique-key

Is the Sql Server Unique Key also an Index?

I've got a column in a table (eg. UserName) which I want to make sure is unique. So I create …

sql-server indexing unique-key

Unique keys in Entity Framework 4

An existing DB schema has unique, non-primary, keys, and some foreign keys that rely on them. Is it possible to …

entity-framework entity-framework-4 unique-key

Find or insert based on unique key with Hibernate

I'm trying to write a method that will return a Hibernate object based on a unique but non-primary key. If …

java hibernate unique-constraint upsert unique-key

Generating a truly unique order id in PHP?

I'm considering using this: http://phpgoogle.blogspot.com/2007/08/four-ways-to-generate-unique-id-by-php.html My idea is to use a mixture between 2 and 3. But …

php unique-key

Is Unique key Clustered or Non-Clustered Index in SQL Server?

I am new to SQL Server and while learning about clustered index, I got confused! Is unique key clustered or …

sql-server clustered-index unique-key

MySQL unique column string

Currently I have this table in my database: CREATE TABLE `twMCUserDB` ( `id` int(11) NOT NULL AUTO_INCREMENT, `mc_userName` text …

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Solr Composite Unique key from existing fields in schema

I have an index named LocationIndex in solr with fields as follows: <fields> <field name="solr_id" …

java solr solrj unique-key solr-schema

What should be the unique ID of a machine? Its motherboard ID? Windows Product ID?

I want to retrieve the unique ID of a machine. Like others I also did a lot of research, and …

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