For example, I create level 1 2 3 three types of work items. then I want to customize a link type which only link level 1 to level 2, but can`t level 1 to level 3 directly. Is it possible? How?
This is not possible at least from looking at the attributes of a linktype which are referenceName, ForwardName, ReverseName and TopologyType. You can enforce a parent/child relationship that isn't circular but I don't believe you can say "and do not allow this WI type to be a child of this WI when linking."
You do have the ability to create custom link types; however, that will only insure a relationship and not scope it to work item type.
For example, out of the box the CMMI template you can create a bug that has a child of WI Requirement of type Scenario which typically isn't a supported workflow (and isn't if you are trying to be CMMI compliant).
I would take a look at Working with Link Types.
Related
I have been asked by a customer to develop a "product configurator", and i need some inputs on how to handle the DB part of the project.
Each product can have a subset of different precreated attributes.
The minimum is 1 attribute, but there is no maximum.
Some attributes have dependencies/relationships with other attributes.
Eg. If the product is a chair, you need to choose the material (wood, plastic, metal), and you need to choose which type of legs the chair shoud have.
If the Product is a cabinet, you still need to choose a material, but instead of legs there will be different doors to choose from etc.
Each of these attributes might have subattributes. Eg. the door has a color, a size and a doorhandle.
Then the door handle has a material, a type and so on.
This ultimatly ends up in a multi-layered attribute-tree.
By itself this isnt too complicated to code, however the customer wants to be able to manage (Create, update and delete) all products, attributes and relationships between attributes, within the webapp.
So coding the relationship-part isn't a viable solution.
I have gone with a EAV model to facilitate the "potential unlimited" amount of attributes each product can have.
But i am struggling to figure out how to go about the "attribute relationships".
A simplified version of my DB design looks like this:
If each product could subscribe to groups of attributes that is legal. Then each attribute belongs to a group like "wood group".
Then the user could set the groups of attributes against a product that should need to be answered to configure a product.
With regards managing a tree, you could use a column type of hierarchyid . Or construct an outline string as key field.
An outline for example
1.
1.1.
1.1.1.
1.2.
2.
2.1.
I am accessing flight reservation application built in SAP.
The application has a section on catering which contains: BC_MEAL, BC_MEALT, BC_STARTER, BC_MAINCOURSE, BC_DESSERT.
However, there are no such tables prefixed with BC_.
The tables are SMEAL, SMEALT, SSTARTER, SMACOURSE, SDESSERT instead.
Why is this discripency due to? How does SAP manage to convert application names into table names.
You're looking at the Data Modeler (SD11) and trying to compare it to the Data Dictionary / ABAP Dictionary (SE11). The actual table names are assigned to the entities explicitly:
expand BC_FLIGHT
double-click on BC_SFLIGHT
Button Dict. (?)
--> This screen should show the tables and/or views used to represent the entity.
It is worth noting that for many applications, no explicit data model exists (which is why I personally never bothered with the Data Modeler - a tool like this is virtually useless unless everyone else uses it as well).
I have a very large amount of data that would most naturally be represented as a tree:
Category 1
Sub-category 1
data point 1
attribute 1
Sub-cateogry 2
data point 1
attribute 1
attribute 2
data point 2
Category 2
Sub-category 1
Sub-category 1
data point 1
Sub-category 2
data point 1
data point 2
Sub-category 2
data point 1
data point 2
data point 3
...
The individual data points have text and numerical attributes, bit it doesn't really suited for representation as a set of related tables. I would like to be able to perform SQL-like queries, but I would also like to be able to browse through the data in a way that makes the tree structure of the data obvious, like with a file manager.
There's probably some class of application that is ideal for such a thing, but it isn't occurring to me at the moment. Some kind of combination of a database and a tree viewer control? Anyone know what it is I'm looking for? As always, I'm terrified of asking a question in the wrong forum, but I see some related questions here at stackoverflow, so hopefully it's OK. Thanks!
You could make a table like this
id
name
parent_id
This structure would allow for nested categories
You could then make a table that relates category and data points.
The java.swing packages contain several table and tree solutions such as the JTable and JTree classes. JTree can be easily constructed to produce the tree structure you are looking for (looks like a file directory.)
The JTable class can be used to create sortable and searchable tables, although you would have to borrow or write your own sort & search methods.
Although these are from Java, other languages offer similar structures that may serve your needs without using a database. That being said, "mySQL" is a very easy to use database and you can download the community DB package for free.
I've got a table in my database storing items:
Items
-------
ItemID
Name
...
Etc
and a separate table storing the PK of two different items from the first table. I want to be able to list the one item, and then any number of related items. I've tried searching for examples but haven't found much surprisingly...
RelatedItems
------------
ItemID
RelatedItemID
If I have four products, whose IDs are 1, 2, 3 and 4... and 1 is related to 2 and 3 I might have data that looks like this:
ItemID RelatedItemID
1 2
1 3
4 1
I am then modeling them in the Entity Framework Designer, and the designer automatically adds an association from the Items table to itself (many to many). The designer also adds two navigation properties, if I use the first property on Item #1 I get all items where Item #1 is in the first column, and if I use the second property I get all the items where Item #1 is in the second column.
I however just want to have one navigation property where I can say Items.RelatedItems and it returns all the items that the above two properties would when combined. I know I can join the two results after the fact but I can't help to think I'm doing something wrong and there is a better way.
Hopefully this is all clear enough.
It sounds like SQL schemas just aren't very good at modeling the concept you're looking for. The schema you've chosen would work well if you want to establish a directional relationship (item A is related to item B, but item B may or may not be related to item A). If you were looking for a grouping-style relationship (Items A and B are in the same group), I can think of a different approach you'd use. But I can't think of a good way to model an inherently bi-directional relationship using a traditional relational database.
Some workarounds might be to use a View that joins the two results, or to use triggers to make sure that every mapping from A to B has a corresponding mapping from B to A, so that both of the properties always return the same objects.
If you have an instance of an Item, call it item, then the following will give you the related items...
item.RelatedItems.Select(ri => ri.Item);
Your RelatedItems property on item (ie the first navigation property you mentioned) will be a collection of RelatedItem objects, each of which has two navigation properties of its own, one of which will be named Item and will be a link to the related item.
Note that this is air code, as I'm not in front of anything I can test this on right now, but I think this will do what you want.
If you want to make it simpler, you can write an extension method to wrap up the Select(), something like this...
public static IEnumerable<Item> RelItems(this Item item) {
return item.RelatedItems.Select(ri => ri.Item);
}
Then you could just do...
item.RelItems();
Note that I couldn't name the extension method RelatedItems, as that would clash with the navigation property that EF would have created for the second table. That's perhaps not a good name for that tables, as it's not the actual items, rather the IDs of the items. Either way, the above code should work.
I have a problem naming the elements in my application's data model.
In the application, the user has the possibility to create his own metamodel. He does so by creating entity types and a type defines which properties an entity has. However, there are three kinds of entity types:
There is always exactly one instance of the type.
For instance, I want to model the company I am working for. It has a name, a share price and a number of employees. These values change over time, but there is always exactly one company.
There are different instances of the type, each is unique.
Example: Cities. A city has a name and a population count, there are different cities and each city exists exactly once.
Each instance of the type defines multiple entities.
Example: Cars. A car has a color and a manufacturer. But there is not only one red mercedes. And even though they are similar, red mercedes #1 is different from red mercedes #2.
So lets say you are a user of this tool and you understood the concept of these three flavors. You want to create a new entity type and are prompted to choose between option 1, 2 and 3. How would you name these options?
Edit:
Documentation and help is available to the user. Also the user can be expecteted to have a technical/programming background, so understanding these three concepts should be no problem.
First of all let me make sure I understand the problem,
Here's what you have (correct me if I'm wrong):
#of instances , is/are Unique
(1,true)
(n,true)
(n,false)
If so,
for #of instances I would use single \ plural
for is\are unique (\ not unique) I would use unique \ ununique.
so you'll get:
singleUnique
pluralUnique
pluralUnunique
That's the best I could think of.. I don't know exactly who are your users and what is the environment, But if you have an option of adding tips (or documentation) that should be used for sure.