I have a CreatedBy column in a table which datatype is a int. SubSonic crashes on this because apperently it uses CreatedBy, CreatedOn, ModifiedBy and ModifiedOn. The By columns need to be strings.
Is there a way to let SubSonic know that it has to ignore these columns?
No, you probably are going to have to rename the column to CreateByUser or something.
You can also change it to a nvarchar(50) and create a column ModifiedBy nvarchar(50) and have it work just fine too.
Yes... this is totally doable. First of all show us the code that makes it crash. I probably know what it is. You are probably trying to do something like this
MyRecord.Save();
Where as you need to do pass in the id of the person that is creating the record aka.
MyRecord.Save(55);
SubSonic knows what datatype your columns are so you don't need to tell it what datatype it is. Also if you look there are overloads of the Save method namely Save(int id), Save(string id), and Save(Guid id). So as long as you use an int,string or guid for your CreateBy column you are good to go, you just need to remember to pass in the ID as SubSonic expects it if you use those columns.
Related
I am learning how to use IBM Cognos and my first task is to create relationships between the tables I have uploaded into Cognos.
Basically, I am trying to tell Cognos to link the id column in the Person Table with the person_id and related_person_id columns in the Relationship Table, as shown here:
However, this does not seem possible since the Match Selected Columns button becomes disabled when I try to also link the related_person_id column.
The reason I need to do this is because person_id and related_person_id are foreign keys - they point to people in the Person Table and explain how they are related.
How can this be accomplished in Cognos?
Thank you.
You can have any number of matches. You need to match a single query item from each side for each match. IIRC, a query item can be used in multiple matches, although that would only be really helpful once relational operators are implemented.
It isn't clear if in your case you want to use person_id and related_person_id as a composite key or if you want a 1.n relationship between ID and person_id and some other relationship (n.1?) between ID and related person ID or if a 1.n relationship between ID and person_id would be sufficient to whatever you are trying to accomplish.
Editorial comment:
It would be really really nice if Cognos introduced relational operators Real Soon Now.
I'm newbie design cassandra data model and I need some help to think out the box.
Basically I need a hierarchical table, something pretty standard when talking about Employee.
You have a employee, say Big Boss, that have a list of employee under him.
Something like:
create table employee(id timeuuid, name text, employees list<employee>, primary key(id));
So, is there a way to model a hierarchical model in Cassandra adding the table type itself, or even another approach?
When trying this line above it give me
Bad Request: line 1:61 no viable alternative at input 'employee'
EDITED
I was thinking about 2 possibilities:
Add an uuid instead and in my java application find each uuid Employee when bringing up the "boss".
Working with Map, where the uuid is the id itself and my text would be the entire Row, then in my java application get the maps, convert each "text" employee into a Employee entity and finally return the whole object;
It really depends on your queries...one particular model would only be good for a set of queries, but not others.
You can store ids, and look them up again at the client side. This means n extra queries for each "query". This may or may not be a problem, as queries that hit a partition are fast. Using a map from id to name is also an option. This means you do extra work and denormalise the names into the map values. That's also valid. A third option is to use a UDT (user defined type). You could then have a list or set or even map. In cassandra 2.1, you could index the map keys/ values as well, allowing for some quite flexible querying.
https://www.datastax.com/documentation/cql/3.1/cql/cql_using/cqlUseUDT.html
One more approach could be to store a person's details as id, static columns for their attributes, and have "children" as columns in wide row format.
This could look like
create table person(
id int primary key,
name text static,
age int static,
employees map<int, employeeudt>
);
http://www.datastax.com/documentation/cql/3.1/cql/cql_reference/refStaticCol.html
Querying this will give you rows with the static properties repeated, but on disk, it's still held once. You can resolve the rest client side.
I have example 'object' with Id, FkAnotherObject, and string. Which attribute I have to use to have ony unique strings in table. Is there any option to do this?
unique="true" should do the trick :-)
Alternatively, unique-key allows you to create multi-column unique constraints.
Disclaimer: I jumped to C# 2008 recently and SubSonic 3 (3.0.0.4) at the same time. I haven't used Linq for much of anything in the past.
Is there an easy way to use the foreign key display value for sorting, rather than the FK Id (which is numeric)?
I've added a new Find method in my ActiveRecord.tt to help with sorting based on a string field name but after doing some testing I realized that even though its working as it should be, I am not handling foreign key fields at all (they are just sorting by their value).
Even if I need to change how I am accessing the data it is early enough in the project to do that. Just looking for suggestions.
LINQ is your friend in this situation, you just need to join your two objects and then sort by the property from your foreign object:
var primaryObjectsSorted =
from primaryObjects in PrimaryObject.All()
join foreignObjects in ForeignObject.All()
on primaryObjects.ForeignId equals foreignObjects.Id
orderby foreignObjects.PropertyYouWantToSortOn
select primaryObjects;
So you have table A which has id of table B as a foreign key and you want to sort table A by the DisplayName column of table B rather than the id of table B?
The only way to achive this is by a join.
SELECT tableA.* FROM tableA INNLER JOIN tableB ORDER BY tableB.DisplayName
In SubSonic2 you can do that, and still be able to update your records if you use the DB.Select(...).ExecuteCollection() method.
I think this should be possible with subsonic3, too.
Howevery, if you don't use the foreign key and the display name is unique, you should just use this value as your foreign key.
Rookie question I know.
I have a table with about 10 fields, one of the fields is a category field. I need this field to exist because of the multiple types of categories. However, one category in this field is wrong and is duplicating results.
So can I delete all records in the table that have "Type320" in the CatDescription field, and how? I want to keep eveerything else as it is in this table; just need to get rid of the records that have that that in that one field
Thanks very much!
EDIT: Thanks for the answer, I did not know how to do this so this is very helpful
However, this is more complicated than I thought. The raw data that I am supplied carries these duplicate records (only duplicate in certain circumstances but they are easy to isolate). This raw data is given to me on a monthly basis in several spreadsheet forms.
It all relates to these ID numbers, and has like 10 fields (xls columns). As I said before one of these is the Category Description field (sorry, this is not a lookup) In certain places this records automatically duplicates itself on output because in the database this comes from, it has to have this sub category for one particular "type"
So....every time there is a duplication, every single bit of information in all fields are exactly the same, with the exception of this CatDescription (one is Type320, and the duplicated record type is "Type321"). However, there are some instances where Type321 is valid on it's own (in which case there is no matching data row with a Type320 catdescription). By matching I mean all data in all fields of a particular record.
A very clear absolute of this is if all fields (data within) of a record with Type320 CatDescription, matches all fields (data within) a record with Type321 CatDescription, then I can delete that record containing Type321 CatDescription. This is true because this is the only situation where this duplication occurs, normally not all of this should match.
This allows all unique records with Type320 and Type321 data (that does not match exactly) to stay; just a it should. This makes sense to me (and hopefully you too :/) but can it be done, and how?
thanks because this is way over my head. I would rather know how to do it in access, but an xls solution is equally as appreciate. heck i would do it in ppt if it would get the job done! :)
I would try with one of these two querys:
DELETE FROM table WHERE CatDescription LIKE '%Type320%';
DELETE FROM table WHERE CatDescription LIKE '*Type320*';
That because the Access database engine could be using * (ANSI-89 Query Mode e.g. DAO) instead of % (ANSI-92 Query Mode e.g. OLE DB/ADO) for the wildcards.
Alternatively, this regardless of ANSI Query Mode:
DELETE FROM table WHERE CatDescription ALIKE '%Type320%';
Note the Access database engine's ALIKE keyword is not officially supported.
Does the CatDescription field look to another table? Is it a a query of those tables that creates what you call duplicate results?
If so, be careful about blaming the table that has CatDescription. Check the look-up table to see if Type320 is found there in duplicate.
If you don't have the problem isolated correctly, then you're likely to delete good records while not fixing the problem.