Composite Foreign Key in Sharepoint List - sharepoint

I have two sharepoint List.
List1 - This contains all users and has primary key as UserId
List2 - This contains all courses and has primary key as CourseId
Now I want to define third list that would have its primary key as composite key.
List3 - This contains users to courses mapping. So the primary key is (UserId, CourseId) combination.
When I define List3, I add columns from the List Settings page. When I create a new column, I can choose Lookup and choose the foreign key from another list. But I am unable to define a composite key. (where the keys come from different list).
Is there a way to define composite key for a list in sharepoint 2010?
Thanks

Sharepoint is not a database and lists are not tables. There are no primary, foreign keys or relations (in the DB sense) in Sharepoint. While the DB metaphor is used to explain Sharepoint it is just an metaphor, not the way Sharepoint works. The closest thing to Sharepoint you can find in the database world are document databases.
Perhaps you are confusing lookup fields with primary keys. A lookup field is a field whose values come from another list. They do not define a relation between the lists. That said, Sharepoint 2010 allows you to enforce deletion constraints so that you can't delete a list item that is used as a lookup value in another list. This is set at the lookup field level and only if the lookup field allows a single choice.
To set the restriction programmatically, use the SPFieldLookup.RelationshipDeleteBehavior property. To set the restriction from the UI, locate the lookup field in the target list's settings, open its settings and enable "Enforce Relationship Behavior" in the Relations section.

Related

Difference Between Columns, metadata, keyword , field

I am a bit confused about terminology. In SharePoint we have a List and it consists of List columns but I have read in one of the site that this can be meta data too.
Taking an example if we have a SharePoint list and if we have a List Columns with name, Job description, age and Income, will this be termed as column, field or metadata?
If this is metadata then how can you define fields/columns/site column?
You may know that Meta Data is nothing but data about data.
In share point context Meta Data can be used as list column also. Consider any excel documents which are classified using Phase , Category, Document Type etc. So when ever you see these columns you can identify what kind of document it is.
As per my knowledge key words are nothing but taxonomy. By using these keywords you can classify the items.
Site Column is different. Site Column can be used as list column in any list. For eg. Consider the Age. In your site you are using Age column repeatedly in your lists/libraries. So instead of creating Age column in each list you can create only one site column and you can add to required list. In simple words reusable purpose.
Fields are nothing but a columns/site columns. These are related to list.
As Mihir states, the word "metadata" means "data about data". So to have metadata you need to have data. In SharePoint the most relevant example would be documents. Documents are data and you can have data (metadata) about these documents. Mihirs Excel example is an example of this.
Say, you want a document library in SharePoint and these documents have a document type chosen from a list of choices.
To achieve this you need to be able to put a document type on the documents. Since Document libraries in SharePoint is a special kind of list, you can create columns=fields on the list - and the data in these columns becomes metadata for your document.
So on the library you create a field, DocumentType, e.g. as a choice field. The field is setup with possible choices for the document type. So the list fields/columns are used to define metadata on the document(s).
When it comes to pure SP lists it becomes more difficult to talk about metadata. For what is it data about? In case of an employee I don't think you can define it as metadata, expect if you treat the physical person as "the data". However, I don't think it technical make a difference. You have your datamodel of the employees and implement it using SP lists - that's what they are there for!

Finding Lookup item numerical values in MS Dynamics

I have a site powered by ExpressionEngine 2.5.x, using Freeform, integrated to post form data to MS Dynamics CRM 2011. The extension is nicely scalable, I can change the mapping, all that excellent stuff. My problem is how to find mapping values for Lookup fields in MS Dynamics.
I am trying to map form fields from the site forms, into MS Dynamics. Some of the fields are Lookups, in MS Dynamics. Our mapping calls out the numerical value of the Lookup item, rather than its name. (Which is good, because ppl can change the text names in the MS Dynamics console without breaking the mapping.)
My question is: I know how to find the actual back-end field names of form fields within MS Dynamics. But how to I find the numerical values of the picklist items and lookup fields? Say I have a Lookup field, for Lead Source (called campaignid). The items are:
web
online
radio ad
flyer
word of mouth
other
I know that when I edit options in an option set, I can see their numerical value. Where can I edit options in a lookup field? I've tried looking under Settings > Customizations > Customize the System, but didn't see anything called lookup.
Lookups are pointers to entities. They do not have numerical values like regular option sets. So I guess that you will have entity called Campaign (or lead) so you can check which campaigns exist in the crm DB where each entity will have view in the DB.
Let's see if i understand your question. You don't have a Lookup option like Option Set because a lookup is consequence of a relationship 1:N between two entities. So for edit a lookup you need edit a record of a entity. In lookup fields you don't have numerical values, you have guid that represent individually a record, so in a record a lookup is stored in database as a guid. Check this video.
Check here how find this guid with the record open.
A look-up field is, roughly speaking a pointer to en entity (in C# it's referred to as EntityReference instead of Entity) and it consist mainly of a guid and logical name of something.
Usually, in the code, when you have an entity, in order to access the fields of its lookup-connected entity, you'll need to make an extra query for that.
So, if you have a Contact instance and need to see the address of its parent customer, you'll have to get the guid and logical name (in this case it'll be Account) and retrieve the data for it separately.
EDIT:
Suppose that you have created an instance of Contact entity and you'd like to access its lastName field. Then you can simply refer to it as follows.
var value = Xrm.Page.getAttribute(“lastName”).getValue();
On the same form, there's also a field that refers to an Account instance (its name is parentCustomerId. Suppose now that you'd like to get the fullName field of the Account. One could expect the following to work.
var account = Xrm.Page.getAttribute("parentCusomterId").getValue();
var name = account.getAttribute("fullName").getValue();
However, that's not going to work, because the parentCutomerId is a look-up field. It means that it only contains a guid (a pointer, a reference) identifying an other entity. You'll have to use it (the guid) in order to fetch the instance that the look-up is "mentioning". Then you'll be able to check it's properties.

How does CRM 2011 auto-wire the StringMapBase table in for Option List picks in Advanced Finds?

The StringMapBase SQL table is the table that holds Option List values that have been added to an entity. When using an Advanced Find in CRM 2011, if you select a pick list column (Option List) value from an entity to be added to the resultset, the Advanced Find mechanism somehow auto-wires in the string value of the pick list from the StringMapBase table instead of showing the StringMapBase's Primary Key value that's actually stored on the record.
I'm in the process of creating SSRS reports that hinge on some Option List values:
// SQL psuedocode
Select...
...
Where Value = 'Some String Value of Interest'
However, I very much dislike the fact that, so far, it looks like I basically have to write in some ad-hoc SQL in order to get the applicable StringMapBase value. In order to do so, I have to hard-code some magic values, which I despise.
Does anyone know by what mechanism the CRM Advanced Find engine auto-wires these values in? Or does it simply do its own join to the StringMap system view or use a SPROC somewhere?
When you use the Filtered views (the only supported way to read data in your report) there will be an additional "logical" column for Bit, Picklist, and Lookup columns. For an attribute named "new_option" you should be able to add "name" to the end of the column name and query "new_optionname".
select new_option, -- Integer
new_optionname -- StringMap joins generated by Filtered Views
from Filterednew_test

How to retrieve from two tables with same foreign key repeated more than once?

How to display the data of tables that are linked by a primary key and foreign key where the foreign key of the data repeats?
For ex. I have two tables, ParentTable and Childtable.
The primary key of ParentTable acts as the foreign key of ChildTable.
There are more than one record with same ParentId in ChildTable. How to retrieve them and display in a single Grid or List or any type of view?
As for the query: if you are using Oracle you may use a CONNECT BY statement in your query; otherwise you can just use a JOIN on the foreign key to retrieve the list of couples Parent-Child and handle them in your C# business logic.
As for the presentation: this is the classic tree structure, so you may find a Treeview useful.

Sharepoint: Integrity of lookup fields after a list import

I got a question about the behavior of lookup fields when importing data. I wonder how the lookup fields behave when the list they point to is being replaced/imported. To explain the issue, I will provide a quick example below:
As example, assume we have these two sharepoint lists:
Product Types
-------------
+ Type Name
+ Code Nr
+ etc
Products
--------
+ Product Name
+ Product Type (Lookup field to list "Product Types")
+ etc
In my scenario, the Products List contains production data on the production Sharepoint platform. It is filled with data by the business users.
However the Product Types list contains rather static data and is maintained by the developer.
Now after a development cycle, the developer wants to deploy his new webparts and his new data (product types list). The developer performs the following procedure:
On the dev machine: Export "product type" list using stsadm
On the production machine: Delete all items in the "product type" list
On the production machine: Import the "product type" list using stsadm
This means we basically replace the "product type" list on the production server while keeping the "product" list as it is.
Now the question:
Is this safe? Will the lookup references break under certain circumstances?
Any downside of this import/export procedure?
What happens if someone accesses a "product" during the import? Will the (now invalid) reference clear its own content (become a null value).
What happens if the schema of the "product type" list changes (new column)? Will this cause any troubles?
Thanks for all feedback and suggestions!
Update 1
The imported "product type" items have the same IDs as previously deleted ones.
Update 2
Started a bounty to get some more feedback/opinions.
We have had this exact same scenario before. This is a little tricky, depending upon how you will approach it.
1) Delete and Recreate Product Type list through UI
If you delete and recreate the lookup List(Product Type in your case) through UI, then you will lose the connections because the List's id GUID will change upon recreation. So do not go that route.
2) Delete and Recreate Product Type through a Feature
If you had created the Product Type list through a feature.xml file using the <ListInstance> element, then if you delete that list and then recreate it using the same feature (basically Id attribute of ListInstance remains the same, number of list items, i.e. the number of <Row> elements, may change), the association would be maintained. So if you were adding 5 more product types, then if you had created the list using a feature, you could just delete the list and provision the new one using the same feature with extra info for new items and everything would just work!
As a side note, this is the better approach because if you have to do the upgrade on a lot of servers, then rather than doing list export import via stsadm, feature deactivation and activation is a much more recommended solution. This is how we did it.
3)Deleting all list items from Product Type and adding new ones (list is never deleted)
If you are linking the lookup field (in Product List) to the ID field of the lookup list(Product Type), you have to remember that ID is auto-incrementing, so if you delete all items and then add new ones, then their ID's would be different. Say you had 5 items with ID's (ID field is not shown in UI while editing in Datasheet view) 1-5 in the list. If you delete them and add new items, their ID's would start from 6 and not 1 again. So if your lookup field had link to the item with ID 1 in it, then this method is not going to work because there is no item with ID 1 in the Product Type list anymore. So you might want to really try this out before going to production with this method.
4) Editing the list in place
If the list is not extraordinarily huge, and you only have to make this change to one or two instances, could you not just edit the list directly in the datasheet view on the prod server? When editing in datasheet view, do not delete the item, but just overwrite the values of its columns. And you can add more items if you want. This will make sure your ID's are valid.
I have mostly talked about adding new items to the list. Now if you were deleting existing items, then your lookup fields will be affected because assuming you linked the field by ID, the ID is not present anymore since the item has been deleted. Basically, any method you use, maintaining your ID's is critical.
Now regarding your doubts/questions:
I am not too sure about stsadm export import for a list (never done it myself), but stsadm can be tricky as some operations will work on certain scopes only. So you better try out your exact scenario on a dev env.
What happens during an import is tricky again depending on the exact timing. I am sure SP has its own concurrency mechanisms, but you cannot have a definitive answer as it might probably be different based on the stage of the import. If possible, recommended approach is to do the import during a planned downtime.
Regarding changing schema of the list, a change in the schema of a list will not affect the existing list instances (for the most part). If you do this through UI, I believe SP makes changes to the content DB directly. I am not certain how you intend to do this, but if you were to add a column to an existing list using a feature, the way to do this is during feature activation by adding a new content type to the list and adding your new column to this content type. This way you add the column but do not affect the existing list items.
Good luck...
There are two components to a particular lookup: the field, and the field value. The field value only contains the ID of the item(s) it refers to, and the display field. This information is meaningless without the field, which specifies what list to look at and what field to use as the display field.
The primary reason that a Lookup will break occurs on the field scope: either the list it referred to no longer exists, or the list does not contain the required field. These would generally happen if you deleted and recreated the list, but you aren't doing that. If you do break a lookup's list reference, then the only thing you can do is re-create the lookup, because you cannot configure the list reference for a lookup field once it is created.
The downside of your import/export procedure is that you lose the validity of all currently existing lookup values. A lookup maintains its integrity based on the ID of the item it references. So when the display field changes, it still refers to the same item. If you delete the item, then the lookup no longer references it, even if you create a new item that has the same value for the display field. So you would have to reassign all of the products to the new product types.
It should be noted that if you were to revert the deletion of that item, it would return to being on the lookup! The reference to that ID is kept until the actual lookup value is updated (such as by editing the Product).
All of your now invalid references will be null for purposes of interaction. You won't see anything on display forms, and you won't have the options when you try to update the product. When you do update the product, you update it to what you just set it to, which since you can't set the non-existent IDs, means that there are no more references to those IDs.
Any changes to the Product Type list's schema that do not affect the display field specified for the lookup will not have any effect on the lookup integrity. If you do change the display field in any fashion, and of course if you delete it, then it will break in the same fashion as with the list reference. However, you can set the display field, both in the UI and in the object model, so it is easy to fix this.

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