nullable unique constraint ef

C#
// Add unique nullable index 
string indexName = "IX_UQ_UniqueColumn";
string tableName = "dbo.ExampleClasses";
string columnName = "UniqueColumn";

Sql(string.Format(@"
    CREATE UNIQUE NONCLUSTERED INDEX {0}
    ON {1}({2}) 
    WHERE {2} IS NOT NULL;",
    indexName, tableName, columnName));
Source

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