I understand that Entity Object Definition is XML data that represents metadata and corresponds to DB table.
Example:
<Entity
xmlns="http://xmlns.oracle.com/bc4j"
Name="Departments"
Version="11.1.1.53.3"
DBObjectType="table"
DBObjectName="DEPARTMENTS"
AliasName="Departments"
BindingStyle="OracleName"
UseGlueCode="false">
<DesignTime>
<AttrArray Name="_publishEvents"/>
</DesignTime>
<Attribute
Name="DepartmentId"
IsNotNull="true"
Precision="4"
Scale="0"
ColumnName="DEPARTMENT_ID"
SQLType="NUMERIC"
Type="oracle.jbo.domain.Number"
ColumnType="NUMBER"
TableName="DEPARTMENTS"
PrimaryKey="true">
<DesignTime>
<Attr Name="_DisplaySize" Value="22"/>
</DesignTime>
</Attribute>
I understand that Entity Attributes corresponds to DB table columns.
BUT I CAN`T understand what is Entity Object Instance. I know that it corresponds to one single row from DB table and for every row there is a different EOI, but where can I find it? Any example and simple explanation would be helpful! :)
Entity Object Instance is something like the row data & business logic object oriented representation. Imagine you need to load data from a DB table into memory, you need a collection of rows (for example List<DbTableRow>), each row (DbTableRow) is an object that contains properties according to each table column data types and it's values; Entity Object Instance is something like each DbTableRowobject item of the list.
Hope it helps...
The following URL will have examples about ADF Entity Object
About Entity and View Object
Entity and View Java classes
I know this is an old post. Hope it will be useful for others
Related
I'm working with Bonita BPM 7.5 and in my contract I have defined an object with an aggregated relationship to another object (complex data), my problem starts when in UI designer I show a table of existing objects (aggregated object) to the user for select which object will be referenced by the new object. Do you have any clues to do that? In particular, to create a new object linked to an existing object in DB. In all cases I'm using BDM accesors.
Tahnks in advance.
Regards...
I think the problem you have isn't so much a data matching problem, BDM accessors are the right approach here. Rather the problem is in the visualization of the data for the tables.
Have you considered creating a custom ReST API endpoint to "flatten" the data from your aggregated table for presentation purposes?
I have some problems regarding entity framework and saving to the db.
As my current program works, it deserializes a json-object which results in a list with objects that matches the database. Each of these objectst looks like this:
Every object is a parent with a relation to one child-object.
Each child object have a relation to one or many parent-objects.
After the deserialization is complete each child-objects is created as new object for every parent (meaning I get several instances of the same object).
When i try to save the objects to the db, this offcourse doesn't work since I'm trying to insert many child-objects whith the same pk. I can clearly see that context.childentity.local contains many objects with the same pk.
Is there any easy way to solve this issue? Can I in some way tell EF to refer all duplicates to the same object?
Best regards Anton
I have 2 content types; publisher and campaign. When I create a campaign node, I then need to use entity reference to reference the publishers who will work on this campaign. I have added a reference entity field to my campaign content type however, I need to search and filter through my publishers to find the ones in the right category, then bulk add them using some kind of checkbox next to each. Anyone any idea how I can do this?
Thanks for any help
It looks like the Entity Reference View Widget module might do what you are looking for.
I'm writing my first database application and I've got an ambiguity I can't seem to find an answer for. I have an id field that is the identity set to auto-increment. My issue is trying to determine when the field is incremented. Is the field incremented when I call an instance of the object, when I call the AddObject method of the ObjectContext class, or when I call the SaveChanges method from an Entity model.
In my relational database each table has both a unique ID for that table and one that represents a group of users. After I create an instance of an object for that table I want to run a query (LINQ) that searches two tables to match two records and from one of those tables copy that group ID back to the individual user.
That or it is blatently obvious I know nothing about how relational databases work,
The identity field is handled by the database. It is created by the database when the row is inserted. The generated id is read back by SaveChanges and the entity object is updated.
WHen you add a new row to the database the counter is incremented.
If you have an ambiguity, this usually means that two tables fields are the same name, and your query doesn't know which one you want. Can be solved by defning which table the column is ment for.
I don't know LINQ, so hopefully someone can give you a more direct answer.
There is commonly used method to map object to table (one object - one row in a table; the table is corresponding to object type), i.e., each object's public field is mapped to corresponding column in a table. Most of the ORM Frameworks are based on that mapping method. The question is there any ORM Framework (based on .Net Framework and well suited for C#) which allows to map object onto several rows in a table where each object's field is mapped to corresponding table's row?
I think what you're looking for is an ORM that generates Collection objects for each of your tables.
Look into Propel ORM
Any query that returns more than 1 row returns a TableObjectCollection object that has multiple convenient methods for access.
It is hard to say for all ORM Frameworks existing for today. But mapping in a following way:
(1) class type - table,
(2) class member/field - column of the table,
(3) class instance - row in a table,
is the well known practice. So, the more probable answer is there is no such ORM which maps a particular class instance on several rows. Otherwise, in accord with (2) the class type must has several members/fields represented with the same name but this is hardly possible.