If your number X falls between A and B, and you would like Y to fall between C and D, you can apply the following linear transform: Y = (X-A)/(B-A) * (D-C) + C That should give you what you want, although your question is a little ambiguous, since you could also map the interval … Read more
You can declare unique constraints using the @Table(uniqueConstraints = …) annotation in your entity class, i.e. @Entity @Table(uniqueConstraints={ @UniqueConstraint(columnNames = {“productId”, “serial”}) }) public class InventoryItem { … } Note that this does not magically create the unique constraint in the database, you still need a DDL for it to be created. But seems like … Read more
Here’s the answer I found: Just to make the definition complete, in the Cartesian coordinate system: the x-axis goes through long,lat (0,0), so longitude 0 meets the equator; the y-axis goes through (0,90); and the z-axis goes through the poles. The conversion is: x = R * cos(lat) * cos(lon) y = R * cos(lat) … Read more
Using some reflection and generics in two extension methods you can achieve that. Right, others did mostly the same solution, but this uses less reflection which is more performance-wise and way more readable: public static class ObjectExtensions { public static T ToObject<T>(this IDictionary<string, object> source) where T : class, new() { var someObject = new … Read more
You must make your foreign key nullable: public class User { public int Id { get; set; } public int? CountryId { get; set; } public virtual Country Country { get; set; } }
After digging more, I found the solution as given below. ignore_unmapped should be explicitly set to true in the sort clause. “sort” : [ { “rating”: {“order” : “desc” , “ignore_unmapped” : true} }, { “price”: {“order” : “asc” , “missing” : “_last” , “ignore_unmapped” : true} } ] For further information have a look … Read more
Since the SERVICE_USER table is not a pure join table, but has additional functional fields (blocked), you must map it as an entity, and decompose the many to many association between User and Service into two OneToMany associations : One User has many UserServices, and one Service has many UserServices. You haven’t shown us the … Read more
Why is the notion of a owning side necessary: The idea of a owning side of a bidirectional relation comes from the fact that in relational databases there are no bidirectional relations like in the case of objects. In databases we only have unidirectional relations – foreign keys. What is the reason for the name … Read more
Python 2: res = dict((v,k) for k,v in a.iteritems()) Python 3 (thanks to @erik): res = dict((v,k) for k,v in a.items())
A nested dict is a dictionary within a dictionary. A very simple thing. >>> d = {} >>> d[‘dict1’] = {} >>> d[‘dict1’][‘innerkey’] = ‘value’ >>> d[‘dict1’][‘innerkey2’] = ‘value2’ >>> d {‘dict1’: {‘innerkey’: ‘value’, ‘innerkey2’: ‘value2’}} You can also use a defaultdict from the collections package to facilitate creating nested dictionaries. >>> import collections >>> … Read more