In Microsoft Project, the only way to reset Unique IDs in the past was to change all Unique IDs in a file. This is rarely done but possible to do if someone happened to want the schedule to have Unique IDs in ascending order like the Task IDs. Recently, I was asked if it was now possible to set or change the Unique ID of a singular task. I don't believe that you can and I haven't found any documentation from Microsoft that says that this is possible. Does anyone know if you can in fact set or change the Unique ID of a single task?
No. Nothing has changed--the Unique ID is a calculated field which is another way of saying it's unchangeable by the user.
A very quick search leads to the documentation: Unique ID fields which states:
The Unique ID field contains the number that Microsoft Office Project automatically designates whenever a new task, resource, or assignment is created in the current project. This number indicates the sequence in which the task, resource, or assignment was created, regardless of placement in the schedule.
There are several categories of Unique ID fields.
Data Type Integer
Unique ID (task field)
Entry Type Calculated
How Calculated As you create new tasks, Project adds a unique number to each task in the project. This number is unique in that it is never rearranged or reused if the task is moved or deleted.
Related
I'm quite new to DynamoDB, but have some experience in Cassandra. I'm trying to adapt a pattern I followed in Cassandra, where each column represented a timestamped event, and wondering if it will carry over gracefully into DynamoDB or if I need to change my approach.
My goal is to query a set of documents within a date range by using the milliseconds-since-epoch timestamp as an Attribute name. I'm successfully storing the following as each report is generated with each new report being added under its own column:
{ PartitionKey:customerId,
SortKey:reportName_yyyymm,
'#millis_1#':{'report':doc_1},
'#millis_2#':{'report':doc_2},
. . .
'#millis_n#':{'report':doc_n}
}
My question is, given a millisecond-based date range, and the accompanying Partition and Sort keys, is it possible to query the set of Attributes that fall within that range or must I retrieve all columns for the matching keys and filter them at the client?
Welcome to the most powerful NoSQL database ;)
To kick off with the positive news, there is no way to query out specific attributes. You can project certain attributes in a query. But you would have to write your own logic to determine which attributes or columns should be included in the projected query. To get close to your solution you could use a map attribute inside an item with the milliseconds as a key. But there is another thing you have to be aware of when starting on this path.
There is a maximum total item size of 400KB for each item in DynamoDB, including key and attribute names.(Limits in DynamoDB Items) This means you can only store so many attributes in an item. This is especially true if you intend to put the actual report inside of the attribute. Which I would advise against, also because you will be burning up read capacity units every time you get one attribute out of the whole item. You would be better of putting this data in a separate table with the keys in the map. But truthfully in DynamoDB I would split this whole thing up, just add the milliseconds to the sort key and make every document its own item. That way you can directly query to these items and you can use the "between" where clause to select specific date-time ranges. Please let me you meant something else.
I'm working on a website that mostly displays items created by registered users. So I'd say 95% of API calls are to read a single item and 5% are to store a single item. System is designed with AWS API Gateway that calls AWS Lambda function which manipulates data in DynamoDB.
My next step is to implement voting system (upvote/downvote) with basic fetaures:
Each registered user can vote only once per item, and later is only allowed to change that vote.
number of votes needs to be displayed to all users next to every item.
items have only single-item views, and are (almost) never displayed in a list view.
only list view I need is "top 100 items by votes" but it is ok to calculate this once per day and serve cached version
My goal is to design a database/lambda to minimize costs of AWS. It's easy to make the logic work but I'm not sure if my solution is the optimal one:
My items table currently has hashkey slug and sortkey version
I created items-votes table with hashkey slug and sortkey user and also voted field (containing -1 or 1)
I added field votes to items table
API call to upvote/downvote inserts to item-votes table but before checks constraints that user has not already voted that way. Then in second query updates items table with updated votes count. (so 1 API call and 2 db queries)
old API call to show an item stays the same but grabs new votes count too (1 API call and 1 db query)
I was wondering if this can be done even better with avoiding new items-votes table and storing user votes inside items table? It looks like it is possible to save one query that way, and half the lambda execution time but I'm worried it might make that table too big/complex. Each user field is a 10 chars user ID so if item gets thousands of votes I'm not sure how Lambda/DynamoDB will behave compared to original solution.
I don't expect thousands of votes any time soon, but it is not impossible to happen to a few items and I'd like to avoid situation where I need to migrate to different solution in the near future.
I would suggest to have a SET DynamoDB (i.e. SS) attribute to maintain the list of users who voted against the item. Something like below:-
upvotes : ['user1', 'user2']
downvotes : ['user1', 'user2']
When you update the votes using UpdateExpression, you can use ADD operator which adds users to SET only if it doesn't exists.
ADD - Adds the specified value to the item, if the attribute does not
already exist. If the attribute does exist, then the behavior of ADD
depends on the data type of the attribute:
If the existing data type is a set and if Value is also a set, then
Value is added to the existing set. For example, if the attribute
value is the set [1,2], and the ADD action specified [3], then the
final attribute value is [1,2,3]. An error occurs if an ADD action is
specified for a set attribute and the attribute type specified does
not match the existing set type. Both sets must have the same
primitive data type. For example, if the existing data type is a set
of strings, the Value must also be a set of strings.
This way you don't need to check whether the user already upvote or downvote for the item or not.
Only thing you may need to ensure is that the same user shouldn't be present on upvote and downvote set. Probably, you can use REMOVE or ConditionExpression to achieve this.
I've been creating a consumer who "grants" ids to clients when they perform certain tasks. It occurred to me at some point that it might be entirely superfluous to worry about the path before I do a .push().name() to create new ids.
Does it matter what path I run the .push().name() on to create a unique ID? Does Firebase generate the IDs entirely based on timestamp, without regard to the path the ID will be assigned to?
Currently, push() ids are generated based on timestamps (along with some randomness). The path on which the id is being pushed is not used as part of the id.
My friends and I have started creating an e-commerce website using asp.net (vb.net). We are newbies and don't know much about it.
Can anybody show me how we can automatically generate unique reference id for each client who is purchasing the product from the website?
You can generate unique id's in database table by providing a column which will have a primary key or unique key assigned to it.and you can set auto increment property of that particular column on so it will increment automatically for each new customer entry.
You can also search the web in the mean time for better approach
There are a lot of ways and methods, but you can use the following command:
Dim user_id As Guid = Guid.NewGuid()
That will generate a unique Id for you.
You can also generate the new id automatically in your database table. Just make sure to create column with data type uniqueidentefier and assign it a default value property newid()
I'm looking for a fast & elegant way of converting my object IDs with descriptive names, so that my autogenerated routes look like:
/products/oak-table-25x25-3-1
instead of
/products/5bd8c59c-fc37-40c3-bf79-dd30e79b55a5
In this sample:
uid = "5bd8c59c-fc37-40c3-bf79-dd30e79b55a5"
name = "Oak table (25x25) 3/1"
I don't even know how that feature could be named, so that I might google for it.
The problem that I see so far is the uniqueness of that "url-object-name", for example if I have two oak tables 25x35 in the db, and their names differ too little to be uniquely url-named but enough to fool the unique constraint in the db.
I'm thinking of writing that function for name-transform in SQL as an UDF, then adding a calculated field that returns it, then unique-constraining that field.
Is there some more mainstream way of achieving that?
One method is that employed by stackoverflow.com which in your case would be:
/products/5bd8c59c-fc37-40c3-bf79-dd30e79b55a5/oak-table-25x25-3-1
This ensures uniqueness, however the length of the UUID may be a deterrent. You may consider adding a sequential int or bigint identity value to the products table in addition to the uniqueidentifier field. This however would require an additional index on that column for lookup, though a similar index would be required for a Url having only a descritive string. Yet another method would be to use a hash value, seeded by date for instance, which you can compose with the descriptive name. It is simpler to rely on a sequential ID value generated by a database, but if you envision use NoSQL storage mechanisms in the future you may consider using an externally generated hash value to append.
Identity should have 2 properties: it should be unique and unchangable. If you can guarantee, that /products/oak-table-25x25-3-1 will never change to /products/oak-table-25x25-3-1-1 (remember, user can have bookmarks, that shouldn't return 404 statuscode)- you can use name as url parameter and get record by this parameter.
If you can't guarantee uniqueness or want to select record more faster - use next:
/products/123/oak-table-25x25-3-1 - get record by id (123)
/products/123/blablabla - should redirect to first, because blabla no exists or have anoher id
/products/123 - should redirect to first
And try to use more short identities - remember, that at web 2.0 url is a part of UI, and UI should be friendly.
MVC routing (actions) will handle spaces and slashes in a name. It will encode them as %20, and then decode them correctly.
Thus your URL would be /products/oak%20table%2025x25-3%2F1
I have done something very similar in an eCommerce platform I am working on.
The idea is that the URL without the unique ID is better for SEO but we didn't want the unique ID to be the product name that can change often.
The solution was to implement .NET MVC "URL slug only" functionality. The product manager creates "slugs" for every product that are unique and are assigned to products. These link to the product but the product ID and name can be changed whenever.
This allows:
domain.com/oak-table-25x25-3-1
to point to:
/products/5bd8c59c-fc37-40c3-bf79-dd30e79b55a5
(The same functionality can be used on categories too so domain.com/tables can point to domain.com/category/5b38c79c-f837-42c3-bh79-dd405479b15b5)
I have documented how I did this at:
http://makit.net/post/3380143142/dotnet-slug-only-urls