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Data Model Editor in Software Implement 3 of 9 in Software Data Model Editor




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Data Model Editor using software toincoporate code 39 extended with asp.net web,windows application datamatrix The Data Mod Code 39 for None el Editor is a data modeling tool provided by Xcode that makes the job of designing a data model quite easy. It displays the browser as well as a diagram view of the data model. The Browser view displays two panes, the Entity pane and the Properties pane, for defining entities and their respective properties.

The diagram view displays rounded rectangles that designate entities and lines to show relationships among the entities.. Adding an entity To add an en Code 3 of 9 for None tity to our data model, perform the following steps: 1. Invoke the data modeling tool by double-clicking the prob.xcdatamodel file in the Resources group found in the Xcode Project window.

2. Xcode"s data modeling tool will open and we will find that an entity by default is already created for us by the name: Event (as shown in the next image) with an attribute: timeStamp..

[ 81 ]. Designing a Data Model and Building Data Objects for Customers 3. We can de lete or rename the default entity Event as desired. Let us select the default Event entity and delete it by clicking on the minus (-) button in the Entity pane followed by either choosing plus (+) button in the Entity pane or by choosing Design .

Data Model Add Entity option from the menu bar. This will add a blank entity (by the name Entity) to our data model, which we can rename as per our requirements. Let us set the name of the new entity as: Customer.

. 4. Automatic Code-39 for None ally, an instance of NSManagedObject will be created to represent our newly created Customer entity. The next step is to add attributes to this entity.

. Adding an attribute property We want to a barcode 3 of 9 for None dd three attributes by name name, emailid, and contactno to the Customer entity. Let"s follow the steps mentioned next for the same: 1. Select the entity and choose the Design .

Data Model Add Attribu Code 39 for None te option from the menu bar or select the + (plus) button in the Property pane. A menu with several options such as Add Attribute, Add Fetched property, Add Relationship, and Add Fetch Request will pop up. 2.

We select the Add Attribute option from the popped up menu. We see that a new attribute property is created for our Customer entity by a default name: newAttribute in the inspector. 3.

Let us rename our new attribute as: name (as we will be using this attribute to store the names of the customers).. [ 82 ]. 4 . 4. Then, we set the type of the name attribute to String as shown in the next screenshot (as names consists of strings):. 5. Below the Software ANSI/AIM Code 39 Name field are three checkboxes: Optional, Transient, and Indexed. Though we will be using the Optional checkbox for the name attribute, let us see the usage of all three: Optional: If this checkbox is checked, it means the entity can be saved even if the attribute is nil (empty).

If this checkbox is unchecked and we try to save the entity with this attribute set to nil, it will result in a validation error. When used with a relationship, if the checkbox is checked it means that the relationship can be empty. Suppose that we create one more entity say: Credit Card (where information of the customer"s credit card is kept).

In that case, the relationship from customer to the credit card will be optional (we have to leave this checkbox checked) as a customer may or may not have a credit card. And if we create an entity say: Product in that case, the relationship from the Customer to the Product cannot be empty as a customer will definitely buy at least a single product (the checkbox has to be unchecked). Transient: This checkbox, if checked, means that the attribute or the relationship is of a temporary nature and we don"t want it to be stored (persist) in the persistent store.

This checkbox must be unchecked for the attributes or relationship that we want to persist (to be stored on the disk). Indexed: This checkbox has to be checked to apply indexing on the attribute. It is used when we want to perform sorting or searching on some attribute.

By checking this checkbox, an index will be created on that attribute and the database will be ordered on that attribute.. [ 83 ].
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