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What are data properties?

Data has got some properties which needs to be taken care of. These properties are like requirements which need to be met. For data, three types of properties have been defined as mentioned below:
1. Definition related properties
2. Content related properties and
3. Both definition and content related properties

Following are definition related properties:
1. Consistency: This property relates to the compatibility of the same data types from various different sources.
2. Clarity: This property relates to the availability of a definition of the data which is both shared and cleared.
3. Relevance: This property is related to the usefulness of the data when employed in the context of business.

Following are the content related properties:
1. Timeliness: This property relates to the availability of data whenever it is required and it also focuses up on whether the data is being updated regularly or not.
2. Accuracy: This property relates to degree of the closeness of the data with the truth values.

Following are the properties related to both content as well as definition:
1. Cost: This property relates to the cost that is incurred when the data is obtained and is made available for use.
2. Accessibility: This property relates to the how, to whom and where of availability as well as non –availability of the data such as security.
3. Completeness: This property relates to the degree of completeness of the data.

What are transient properties of data?

– For core data there are some transient properties which have always puzzled the developers.
– These properties are defined as a part of the data model but the difference is that they are not considered to be a part of data of the entity’s instance.
– The changes that are made to the transient properties are tracked by the core data and so are recorded for some particular operations such as undo.
– Therefore, we can say that they are just like the usual data properties but with the difference of not being saved in the persistent store.
– Below mentioned are some observations from an individual’s research:
1. Undo and redo can be considered as normal properties.
2. Object will be marked as dirty if the modifications are made to any transient property.
3. Turning an object in to a fault will clear the transient properties.
– The primary use of the transient properties is that the properties that are not to be stored can be counted for the undo support.
– In the case of any key value observation compliant key making any change in such a property will result in marking your object as dirty.
– Caching is recommended for such kind of properties which cannot be stored.
– Some examples of such properties are the attributes (which are of unsupported types) and cross – stores relationships.
– Before saving the property is converted in to something which can be stored and then it is written in to a binary attribute.

What are Changed Properties?

– There are other properties called the changed properties.
– Usually the transient properties have got a null value and the transient properties which are not null are called the changed properties.
– The behavior of the transient properties is just like the persistent properties but their value in the persistent store is null.
– There is a side effect to this which is that after saving the non – null transient property is still considered to be changed even though the object is no dirtier.

Below mentioned are two setter and two getter methods which can be used with one managed object context:
1. The delayed update set access-or
2. The immediate update set access-or
3. The pre calculated get access-or
4. The on demand get access-or
The things can get messed up if you are having multiple contexts in the picture.

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