2015年3月23日 · In ng-options use ng-options="property.data.Bedrooms as instead of ng-options="property.data.SubType as because data.Bedrooms is the property that contains number of bedrooms which should be stored in ng-model. In scope add this function

If col1 is unique, and col2 is unique, then col1+col2 is also unique, so there would be no need for a composite key or constraint. – SteveW Commented Oct 5, 2023 at 19:14

2010年5月7日 · Based on Google's recommendations, I implemented a class that will generate a unique UUID for each device, using ANDROID_ID as the seed where appropriate, falling back on TelephonyManager.getDeviceId() as necessary, and if that fails, resorting to a randomly generated unique UUID that is persisted across app restarts (but not app re-installations).

The UNIQUE constraint does exactly what you want. NULL values can coexist in multiple rows in a column defined UNIQUE. The manual: In general, a unique constraint is violated when there is more than one row in the table where the values of all of …

2015年11月15日 · Here is an extension method for setting unique indexes more fluently: public static class MappingExtensions { public static PrimitivePropertyConfiguration IsUnique(this PrimitivePropertyConfiguration configuration) { return configuration.HasColumnAnnotation("Index", new IndexAnnotation(new IndexAttribute { …

jQuery.unique lets you get unique elements of an array, but the docs say the function is mostly for internal use and only operates on DOM elements. Another SO response said the unique() function worked on numbers, but that this use case is not necessarily future proof because it's not explicitly stated in the docs.

I have to design and implement a reservation system for a hotel. I have an array list of Reservation objects an array list of room objects I want to 'reserve' the room at a given date.

Create all possible unique values that can be created from product_id and branch_id by creating a string separated by a character, in this case -Generate unique random values from this set using the randomElements function. Split the random element back to product_id and branch_id

2012年3月5日 · Unique Key (UK): It's a column or a group of columns that can identify a uniqueness in a row. Primary Key (PK): It's also a column or group of columns that can identify a uniqueness in a row. So the Primary key is just another name for unique key, but the default implementation in SQL Server is different for Primary and Unique Key. By Default:

2013年3月18日 · The constraint could be removed with syntax: ALTER TABLE. As of MySQL 8.0.19, ALTER TABLE permits more general (and SQL standard) syntax for dropping and altering existing constraints of any type, where the constraint type is determined from the constraint name: ALTER TABLE tbl_name DROP CONSTRAINT symbol;