i have a question with cox model.
if I have two surveys with two different time to see how physical activity can impact heart disease (for example)
if I do a analysis HR with the first questionnaire, what analysis should I do for the second questionnaire ?
I ask that because at the second questionnaire we don't have the same sample because of censure ... so do you have any idea please ?
I tried the first survey but I have no idea to do with the second survey
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I am in process of designing my database.
It's a simple online course, which users can earn points by achieving certain goals. For instance, if a user passes a quiz with score over 90, then 50 'iq' points are awarded to student.
My specific question here is, How would I find out the NEXT available award, and how many points are needed to obtain award.
So here is my idea of the tables (very truncated here for brevity of course):
Users table
id
name
points_balance
Awards table
This table holds all available awards.
id
award_name
points
award_sql
The award_sql column holds a sql statement to run to find out if the user is eligible for this award. For example, I could add a sql statement here to check to see if the user logged in three consecutive days. If true, user eligible for this award.
User_awards
Holds the awards a user already obtained
id
user_id
award_id
date_awarded
So the ideal query would do the following:
Check to see if the user qualifies for the award and doesn't already have it
Based on the list returned above, I need to know which which award is CLOSEST in points.
Schema Is Rough Draft
The table structure above is just my first draft.
I am new to writing SQL
If there is a better way to design my tables, I'd love to hear your suggestion.
Thank you for looking. I have looked into using the MIN function, but that's kinda above my skill set right now.
I would design my Awards tables as below:
Instead of the column "award_sql" in Awards table it would be better to have something like "award_status". This column will have a value "y" or "n" based on the user qualifying for the award.
In this design awards.award_status gets populated or loaded after login_history,quiz_results,referral_table and the remaining dependent tables are loaded. Use the award clause SQL to populate award_status column.
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This is my first database schema design. I am trying to develop a small web application for my department which will be used for food cost management. And I am doing this for my learning purpose.
How the food cost management works in my department:
Total members: 15
One admin to keep record of all the cost. he will update the database on a daily basis.
Each member can order only once a day. If anyone has guest on any specific day he can order multiple number of meal.
Usually members pay their bill for a week or two in advance.
one or two persons are responsible for bringing the food from outside and they don't need to pay for their lunch. Transportation cost is also given to them. their food cost+ transportation cost is distributed equally to other 15 members expenses.
Database queries:
From admin perspective:
he will manage/add the daily order. (Table: orders)
he will add the payments for all the members which will be credited against respective member's "Balance" (Table: payments)
he will be able to see an overview of all members' order/cost history and their current balance in a chart for one month at a time.
If any member has negative balance or less than a specific amount of money, it will be notified to admin dashboard.
From member perspective:
he will be able to see his current balance and order/cost history for last one month at a time.
he will be able to see last x number of payment history he made.
Based on the queries I mentioned above I tried to design a database schema which looks like the diagram below:
Elaboration of some attributes:
EPlatenum: Number of extra plate of food brought besides number of plate ordered.
Eplatecost: cost for extra plate of food. this cost is distributed equally among 15members individual cost.
EPersonnum & EPersoncost: Number of extra person involved in bringing the food and their total cost. the cost will be distributed equally among 15members individual cost.
TransCost: transportation cost. the cost will be distributed equally among 15members individual cost.
Questions:
what are the mistakes I have made and how can I overcome them?
For my DailyList table I have used "date" as the primary key.Is it OK to use date as primary key? IF not OK, what can be the primary key here instead?
when I am going to populate a chart overview for 30 months cost/order history the database query will be huge I assume. what approach should I take to optimize the query?
I am looking forward to getting your suggestions on improving the database schema. Please help me correcting my design mistakes and overcome them. Thank you for your patience.
My first impression:
I think payment should be related to order (because user pays for specific order).
I don't know what DailyList is, but if there may be more than two with the same date (and as I can image it may be) you shouldn't use it as a primari key.
Password should be encoded with e.g. SHA (so varchar 15 is to less).
My question is more of trying to understand what and how I can get something done. Here's the thing:
I got a job to build this application for a school to manage student bio data, work-out and handle student information and basic finance management.
Based on requirements I got from meets with my client, I have an ERD of a proposed MySQL Database with 23 different tables. The one part I would like to understand quickly is displaying data based on school terms. There are 3 terms in a year, each with its own summaries at the end of each term. At the end of 3 terms, a year has gone by and a student is promoted or demoted.
So my question is, how can I render my data to show 3 different terms and also to create a new year working out how to either promote a student or make the student repeat the class its in?
23 different tables? I'd like to see that model.
I don't think you should have one table per term. You'll have to keep adding tables every term, every year.
Sounds like a transcript table should have term and year columns that are incremented or decremented as a student progresses through. It should also have a foreign key relationship with its student: it's a 1:1 between a student and their transcript.
I would have a separate transcript table because I'd prefer keeping it separate from basic personal information about a student. A transcript would refer to the courses taken each term, the grade received for each, and calculate overall progress. If I queried for the transcript for an individual student, I should be able to see every year, every term, every course, every grade in reverse chronological order.
This database is linked to SQL tables. I used multiple queries to open duplicate forms because the different criteria. Then I tried creating the search criteria with macros in the where condition. Both ways are extremely slow.
Should this be handled through the "on Load" Even Procedure? With an If statement? to get the results of each query currently used.
From your question the key part that stood out as a potential problem area was the part about using macros in the WHERE clause. The problem with that is you will have to bring lots of records down the wire to your local computer to do the processing.
Its like ringing a car dealer and saying “I would like to by a red car and it has to fit in my garage” The dealer knows what red cars he has (index) but does not know anything about your garage so has to drive each car (record) to your house (computer) and try to fit it in your garage!
If you can move all the processing to the server it would help , so expanding on the car example you ring up and say “I want a red car that is no wider than 4’” The dealer can now just send the cars (records) that match that criteria to your house (computer).
That’s all the help I can be for now until more information is provided
I'm the one-man dev team on a fledgling military history website. One aspect of the site is a catalog of ~1,200 individual battles, including the nations & formations (regiments, divisions, etc) which took part.
The formation information (as well as the other battle info) was manually imported from a series of books by a 10-man volunteer team. The formations were listed in groups with varying formatting and abbreviation patterns. At the time I set up the data collection forms I couldn't think of a good way to process that data... and elected to store it all as strings in the MySQL database and sort it out later.
Well, "later" - as it tends to happen - has arrived. :-)
Each battle has 2+ records in the database - one for each nation that participated. Each record has a formations text string listing the formations present as the volunteer chose to add them.
Some real examples:
39th Grenadier Rgmt, 26th Volksgrenadier Division
2nd Luftwaffe Field Division, 246th Infantry Division
247th Rifle Division, 255th Tank Brigade
2nd Luftwaffe Field Division, SS Cavalry Division
28th Tank Brigade, 158th Rifle Division, 135th Rifle Division, 81st Tank Brigade, 242nd Tank Brigade
78th Infantry Division
3rd Kure Special Naval Landing Force, Tulagi Seaplane Base personnel
1st Battalion 505th Infantry Regiment
The ultimate goal is for each individual force to have an ID, so that its participation can be traced throughout the battle database. Formation hierarchy, such as the final item above 1st Battalion (of the) 505th Infantry Regiment also needs to be preserved. In that case, 1st Battalion and 505th Infantry Regiment would be split, but 1st Battalion would be flagged as belonging to the 505th.
In database terms, I think I want to pull the formation field out of the current battle info table and create three new tables:
FORMATION
[id] [name]
FORMATION_HIERARCHY
[id] [parent] [child]
FORMATION_BATTLE
[f_id] [battle_id]
It's simple to explain, but complicated to enact.
What I'm looking for from the SO community is just some tips on how best to tackle this problem. Ideally there's some sort of method to solving this that I'm not aware of. However, as a last resort, I could always code a classification framework and call my volunteers back to sort through 2,500+ records...
You've tagged your question as PHP related - but it's not.
You are proposing substituting the real identifiers with surrogate keys (ids) however the real identifiers are intrinsically unique - so you're just making your data structure more complicated than it needs to be. Having said that, the leaf part of the hierarchy may only be unique within the scope of the parent node.
The most important question you need to address is whether the formation tree is always going to be two levels. I suspect that sometimes it may be one and sometimes it may be more than 2. The structure you propose is not going to work very well with variable depth trees.
This may help:
http://articles.sitepoint.com/article/hierarchical-data-database
C.