I Have two qvd files Users and Cases.
In Cases I have three fields "creator", "modifier" and "owner". All of this fields are id from Users table.
In my LinkTables.qvs file I join Users to creator by this schema
LOAD 'USERS' as TYPE,
%USER_ID
Resident USERS;
Concatenate
LOAD
'CASES' as TYPE,
%CASE_ID,
CASES.CREATOR as %USER_ID
Resident CASES;
My question, how can I join same object (Users) to Cases in other fields. (%User_Id I define in load from qvd script)
Thanks.
Related
Suppose I have a User Table and a UserProfile Table that I have separated. The two tables have a 1:1 relationship.
User table contains only data like email and password, while UserProfile contains data like first name, last name, phone number, etc.
Does it make more sense that future tables like Projects (for projects of a user) or Ratings (ratings of a user) have a 1:N ratio to the UserProfile table or the actual Account table (User)?
Thanks for tips.
Your users table should have a unique id to identify users throughout your database. In general, this would be an integer, because those are a bit more efficient for indexes.
As for your data model, you would use this user_id for all tables that reference users. This includes userProfiles. In that table, it would be both a primary key and foreign key -- unless this were a type-2 table with version effective and end dates.
Note: I would tend to put all sensitive data in userProfiles -- including the email. An encrypted password would not need to go there. That way, you can better control access to PII ("personally identifiable information").
I am in the process of creating an audit plan using ERD, going off the below image you can see that there's a permissions table with four FK columns referring to the other four tables PK column. I am just confused as to how the IDs will relate to the other tables and how will it show up correctly in the permissions table?
For the Users table, I imported the data from 'master.sys.server_principals.
For the Instance table, I imported the data by using ##SERVERNAME.
For the Databases table, I imported the data from master.sys.databases.
For the Object Types table, I imported the data from master.sys.objects.
Now, I am currently on the permissions table and stuck at this point because I am wondering how will the IDs match from the four other tables (mentioned above and shown in the image link below) to this permissions table. I know I need to query from master.sys.database_permissions to get the information for both columns 'Permissions_Permission_Name' and 'Permissions_Object_Name' but it's just the other four ID columns which I am confused about...(you can ignore the column Permissions_ID)
I'm going to use the Answer field, because there is no space in the Comment editor. This answer is an answer to only part your question, two of the four tables (Databases and Users) I can relate to system tables.
First and foremost: when filling in Id's, you would generate the other table records first, keep the Identity Id's generated, and finally create a new Permission record and fillin the correct indexes there, in each Id field. That counts for any such change when a table contains indexes to other tables. Suppose you know.
Issue is, your structure differs from the system tables. You will need more "permission" records than master.sys.database_permissions, because MsSQL registers these as permissions per principal (role) not permissions per user.
I solved two of the four:
The user is connected to a principal role via master.sys.database_role_members. The Id of the user role can be found in your source as master.sys.database_permissions.grantee_principal_id and the corresponding users that have this principal_id are listed in master.sys.database_role_members.
Your permission a database (ONE database) is defined in your Permission record. The database name in this database record should map to a database on your server. In that database, you will find database_permissions.sys.server_principals. users that have the permissions are (again) found in master.sys.database_role_members.
I'm not sure what you intend to do with the other 2 tables, Instances and Object Types.
Refer ms-docs about the subject at https://learn.microsoft.com/en-us/sql/relational-databases/system-catalog-views/sys-database-permissions-transact-sql?view=sql-server-ver15
I'm new to database logic. I have Owners and Borrowers tables for a rental system. Both of them share similar fields like "email, username, password, etc." and also they differ from each other. My question is: How can I merge these similar fields into one table, because I'm pretty sure that my implementation is wrong. Another problem is that I can't properly determine relationship between Items and Item_statuses
When you design your tables, you don't organize them according to the similarities among the titles of the columns, but according to the relations between them.
Your design is working, you may just remove the 'item_statuses' table and create a 'status' column in the 'items' table.
But, let's do some brainstorming to improve the design and consider more of the business logic. We should ask some questions like:
How frequent will the owner be a borrower?
Should I keep track of all the statuses of the item?
If it is frequent for a person to be a borrower and an owner, we will end with duplicated records in our database, so we will make only one table called 'users' with the required fields, and refer the foreign keys in the 'items' table for the users.
If you should keep track of all the statuses of the item, create a separate table called 'items_log' with fields like 'Date' and with a foreign key that references to the item in the items table.
I would also keep track of all the borrowers of the item, so, I can make a 'item_borrowers' table with 'borrower' that references to the user, and 'item' that references to the item with fields like 'Date'.
Also keep in mind that you should store hashed password in the database not plain-text.
I'm creating a module for DNN 7.3.4. Another bought module creates new users. I need to display a list of those users in my module using an SQL statement. However the other module creates them in the table aspnet_Users and also adds their details into the Users table.
I cant see how I can link the records in both tables as the userid in the aspnet_Users table takes the form of "6c9c37b9-0a9a-4394-aad5-715e63681024" whereas the Users table UserID field contains "1".
The link there is the "username" field in both tables.
If you are trying to display users from your own module, you should only look at the DNN Users table, and UserPortals, I would ignore everything in the ASPNET_ tables, just let DNN maintain that link.
I currently have this database structure:
One entry can have multiple items of the type "file", "text" and "url".
Everyone of these items has exactly one corresponding item in either the texts, urls or files table - where data is stored.
I need a query to efficiently select an entry with all its corresponding items and their data.
So my first approach was someting like
SELECT * FROM entries LEFT JOIN entries_items LEFT JOIN texts LEFT JOIN urls LEFT JOIN files
and then loop through it and do the post processing in my application.
But the thing is that its very unlikely that multiple items of different types exist. Its even a rare case that more then one item exists per entry. And in most cases it will be a file. But I need It anways...
So not to scan all 3 tables for eveyr item I thought I could do something like case/switch and scan the corresponding table based on the value of "type" in entries_items.
But I couldn't get it working.
I also thought about making the case/switch logic in the application, but then I would have multiple queries which would probabably be slower as the mysql server will be external.
I can also change the structure if you have a better approach!
I also having all the fields of "texts", "urls" and "files" in side the table entries_items, as its only a 1:1 relation and just have everything that is not needed null.
What would be the pros/cons of that? I think it needs more storage space and i cant do my cosntraints as i have them now. Everything needs also to be null...
Well I am open to all sorts of ideas. The application is not written yet, so I can basically change whatever I like.
You have three different entity types (URL, TEXT, FILE) being linked to the primary ENTRIES table via the intermediary table ENTRIES_ITEMS, and you are violating normal form with this "conditional join" approach. Given your structure, it is impossible to declare a foreign key constraint on ENTRIES_ITEMS.id because the id column could reference the URLS, the TEXTS, or the FILES table. To normalize the ENTRIES_ITEMS table you would have to add three separate fields, urlid, textid, and fileid and allow them to be nullable, and then you could join each of the three entities tables to the ENTRIES table via your linking table. The approach you are taking is very commonly found in legacy databases that were not SQL92-compliant, where the values were grabbed from the entities tables programmatically/procedurally rather than declaratively using SQL selects.
I would first consider adding a column to your "entries_items" table that contains an XML representation of texts, urls, and files. I can't speak for MySQL, but SQL Server has fantastic facilities for handling XML. I bet MySQL does too.
If not a state-of-the-art technique like that, then I would consider going retro and just having one items table with many nulls, as you already considered.
This may get you started, but wil not resolve hierarchical structure (parent_id) of entries and entries_items.
select *
from entries as e
join entries_items as i on i.entry_id = e.id
left join texts as t on t.item_id = i.id and i.type = 'text'
left join urls as u on u.item_id = i.id and i.type = 'url'
left join files as f on f.file_id = i.id and i.type = 'file'
;
If considering the model cleanup, this may be a starting point.