Search results
- Dictionaryunique/juːˈniːk/
adjective
- 1. being the only one of its kind; unlike anything else: "this discovery was unique in history" Similar Opposite
noun
- 1. a unique person or thing: archaic "some of Lamb's writings were so memorably beautiful as to be uniques in their class"
Powered by Oxford Dictionaries
The OP is asking about whether it is possible to add an Attribute to an Entity class for a Unique Key. The short answer is that it IS possible, but not an out-of-the-box feature from the EF Core Team. If you'd like to use an Attribute to add Unique Keys to your Entity Framework Core entity classes, you can do what I've posted here
Sep 19, 2013 · Unique indexes in EntityFramework Core: First approach: protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder.Entity<Entity>() .HasIndex(p => new {p.FirstColumn , p.SecondColumn}).IsUnique(); } The second approach to create Unique Constraints with EF Core by using Alternate Keys. Examples. One column:
Nov 15, 2015 · 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 { IsUnique = true })); } }
Jun 30, 2021 · The answer here depends on exactly what you mean by "I want to 'b' and 'cc' fields be unique." Mongoose implements the unique constraint by creating a MongoDB index on that field with the unique:true option. MongoDB enforces the unique option by not allowing the same value to be stored twice in the index.
Feb 24, 2018 · A plain UNIQUE constraint on a column, other than via an index, is not supported. You can enforce this uniqueness property by setting the unique property of an @Index annotation to true. The following code sample (Java) prevents a table from having two rows that contain the same set of values for the firstName and lastName columns:
Jul 4, 2009 · Generating unique names in the preprocessor is difficult. The closest you can get is to mangle __FILE__ and __LINE__ into the symbol as popcnt suggests. If you really need to generate unique global symbol names, then I would follow his suggestion about using something like M4 or a Perl script in your build system instead. You might not need ...
Jan 22, 2017 · I'm creating the schema for a mongo document and I can do everything except prevent duplicates in a non-object array. I'm aware of the addToSet, but I'm referring to Mongo Schema. I don't want to
Jul 15, 2017 · If you only want to compiler to differentiate between the two, you can just add dummy unique members which make no runtime difference: class HumanId extends id { private _humanId: HumanId; // Could be anything as long as it is unique from the other class } class AnimalId extends id { private _animalId: AnimalId; }
Apr 28, 2015 · How can I create an on-the-fly unique variable name with C++? Solution: #define CAT2(a,b) a##b #define CAT(a,b) CAT2(a,b) #define UNIQUE_ID CAT(_uid_,__COUNTER__) int main(int argc, char* argv[]) { int UNIQUE_ID = 1; int UNIQUE_ID = 2; return 0; }
Given the following JSON schema, is it possible to indicate that the "name" property shall be unique (i.e. there should NOT be two items with the same "name" in the "elements" array.
