I am relatively new to database design so I am still learning a lot. What I am working on is an online time card clock. I am just messing around with it to learn more. My full time job is working for my uncle operating heavy equipment and he has expressed some headaches to me. When going over time cards several employees hand writing is hard to read, several employees don't add the hours correctly so he always has to double check their math, plus some people don't hand in the time sheets on time. Most of the employees have smart phones so my solution is to just make a simple website that has a button for "Clocking in" and "Clocking out" it would also contain several text fields to describe what the employee operated that day and the job site they were on. All of this will be added to a database that will be emailed to the boss at the end of the work week. My question is what would be the best way to setup a database for this? Should I add a separate table for each employee or keep it all in one table? There will be about 20 employees that will use the site. Thanks in advance for any help.
General database principles:
Think about object orientation. Classes of objects.
An "Employee" is one such class, therefore you should have one table that stores employees.
An "Event" such as clocking in or clocking out is a general class of two specific cases, e.g. ClockIn and ClockOut.
You could consider one table to store an Event with a field for the date and time of the event, one field for the employee (a foreign key), one field indicating whether it's in or out
You could alternatively consider one table for ClockIn, one for ClockOut, but this may not be advantageous depending on how you wish to scan the data later when printing reports. I'd personally recommend against this approach, just point out that it's an option.
Ideally, every table should have a numeric primary key
Think of key-value pairs
Employee
1 Jon Doe
2 Juan Gomez
etc...
Event
1 2012-11-29 08:59 Clock In 2
This translates to Juan Gomez clocking in today just before 9am
Related
I'm a little stumped on whether i can make this process of changing addresses easier. I'll explain the situation:
Basically I have three entities, Students, Addresses, StudentsAddresses. Students have many addresses, since they can change alot and rapidly (especially foster kids / homeless kids). So ill be changing them a lot. However based on each address I Want a user to attach (enter it via the UI) the price it would cost to pick that student up via bus service. So my initial thought was, ok, let me attach a column onto my join table 'StudentsAddresses' called 'dailyPrice', this is the cost for each day a student is picked up, and another column called 'adjustmentPrice', which is an additional cost for whatever special circumstance that requires extra work to pick up a student. Is my thinking going to cause me problems the more students I have in the future? Will it get harder to manage?
Another option I thought about, was creating a new Table called Pricing. And another join-type table called StudentsAddressesPricing
StudentsAddressPricing has three columns,
studentId
addressId
pricingId
each field connects the three together. So if i ever needed Students, with their addresses, and the pricing, i would query this table and eager load Students, Addresses, and Pricing. Does this approach seem much cleaner since i've abstracted pricing out a bit? Trying to determine the best way to go about this without having to many headaches in the future incase I wan't to add more attributes pricing related, or address related.
And then I even thought, hey what if pricing is just different for one day? How would I even consider that. Would I need a different kind of entity to handle that? Is doing alot of joins going to hurt my application performance?
Just looking for some insight on how others would do it, and criticism on why im off the ball.
The main question you should ask yourself is: on what does the price depend?
If the price is determined by the address, you might as well add it to addresses. If the price also depends on the student (e.g., depending on their financial situation), it would make sense to put it into studentsaddresses.
In other words: The table where the price is stored should have foreign keys to everything outside the table that determines the price. If that makes it fit into one of the existing tables, keep it there.
If I have a list of theatres and in each theatre there are several classes of tickets eg. Rs.120, Rs.100 etc. These classes will apply for morning, noon and night shows. So all the classes of tickets will be available for all the shows(Many to Many Relationship) I need to model this as a database. I have a problem in modelling the classes and show timings. This makes the data base redundant.
Input Excel data
A good rule of thumb, is when you hit redundant data, make a new table.
Here is how I would break it down, though you could break it down further (also see a term normalize):
Tables:
theater_tbl
ticket_tbl
classes_tbl
relate each ticket to a class, and each theater may sell one or more tickets of any given class.
Information like address of theater go with theater_tbl
Ticket pricing would go in the ticket table under the type of ticket, unless I misunderstand what a class of ticket is, then the pricing should go there.
The time of day a ticket relates to should go in the ticket table.
This should get you started. To go further, you could break down show times into another table, and relate classes/tickets to those show times.
Its hard to draw out without a solid example.
Currently, I have 48 fields.
I'm completely new to access. This is how I decided to connect everything together.
It doesn't seem to be very effective. Could somebody help me understand how to normalize this database?
Should I try to put employee information in one table, job information in another table and then have an equipment lookup table?
The current job, last job, and previous job can all the SAME table. If you sort this table by descending job start date, then then you have current, last and previous. You thus don’t need nor want a separate table for each of these which really amounts to the concept of a “job”. If sorting by date is not enough, then you could add a column called Job Type (current, previous, etc.). Again, we still only using the one table.
The same goes for Equipment. You really don’t care if the limit is 3 last, or 300 last. By building a normalized table, then ONE form can edit all types and you save MASSIVE amounts of coding and building of tables, User interface software, and that of building quires to retrieve + show the last 3 jobs in a form.
The fact that your design with FAR LESS cost of development allows 3 or 300 last jobs is really moot. More important if some manager comes along and now wants you to save the last 4 jobs, you don’t have some massive re-design here. And you can on the fly add new job types. So in place of current, and say previous, you can also have un-completed, or failed jobs. So adding new business rules means again you don’t add a new type of job table, but only a “type” to the one column you already using to define the job as current or previous.
Identify like objects and make one table to store all of them. In your design you have three tables for equipment but each item of equipment has the same fields; they should be one table. Similarly for jobs, each job is pretty much the same; they should be one table. The same for departments.
Figure out one or more column in each table that can uniquely identify the row in the table (that is, if you know the values for those columns it is impossible for there ever to be two rows with those values). These are your primary keys for your tables.
Identify cases in which an item in one table needs to "point to" (refer to) an item in another table. In this case, make sure that the referring table has a set of columns that match the referred-to table.
When you've done that, you'll have the beginnings of a correctly factored relational database design.
We presently use a pen/paper based roster to manage table games staff at the casino. Each row is an employee, each column is a 20 minute block of time and each cell represents what table the employee is assigned to, or alternatively they've been assigned to a break. The start and end time of shifts for employees vary as do the games/skills they can deal. We need to keep a copy of the rosters for 7 years, with paper this is fairly easy, I'm wanting to develop a digital application and am having difficulty how to store the data in a database for archiving.
I'm fairly new to working with databases, I think I understand how to model the data for a graph database like neo4j, but I had difficulty when it came to working with time. I've tried to learn about RDBMS databases like MySQL, below is how I think the data should be modelled. Please point out if I'm going in the wrong direction or if a different database type would be more appropriate, it would be greatly appreciated!
Basic Data
Here is some basic data to work with before we factor in scheduling/time.
Employee
- ID Number
- Name
- Skills (Blackjack, Baccarat, Roulette, etc)
Table
- ID Number
- Skill/Type (Can only be one skill)
It may be better to store the roster data as a file like JSON instead? Time sensitive data wouldn't be so much of a problem then. The benefit of going digital with a database would be queries, these could help assist time consuming tasks where human error is common.
Possible Queries
Note: Staff that are on shift are either on a break or on the floor (assigned to a table), Skills have a major or minor type based on difficulty to learn.
What staff have been on the floor for 80 minutes or more? (They are due for a break)
What open tables can I assign this employee to based on their skillset?
I need an employee that has Baccarat skill but is not already been assigned to a Baccarat table.
What employee(s) was on this table during this period of time?
Where was this employee at this point in time?
Who is on shift right now?
How many staff on shift can deal Blackjack?
How many staff have 3 major skills?
What staff have had the Baccarat skill for at least 3 months?
These queries could also be sorted by alphabetical order or time, skill etc.
I'm pretty sure I know how to perform these queries with cypher for neo4j provided I model the data right. I'm not as knowledgeable with SQL queries, I've read it can get a bit complicated depending on the query and structure.
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MYSQL Specific
An employee table could contain properties such as their ID number and Name, but am I right that for their skills and shifts these would be separate tables that reference the employee by a unique integer(I think this is called a foreign key?).
Another table could store the gaming Tables, these would have their own ID and reference a skill/gametype with a foreign key.
To record data like the pen/paper roster, each day could have a table with columns starting from 0000 increasing by 20 in value going all the way to 2340? Prior to the time columns I could have one for staff where each employee is represented with their foreign key, the time columns would then have foreign keys to the assigned gaming Tables, the row data is bound to have many cells that aren't populated since the employee shift won't be 24/7. If I'm using foreign keys to reference gaming Tables I now have a problem when the employee is on break? Unless I treat say the first gaming Table entry as a break?
I may need to further complicate things though, management will over time try different gaming Table layouts, some of the gaming Tables can be converted from say Blackjack to Baccarat. this is bound to happen quite a bit over 7 years, would I want to be creating new gaming Table entries or add a column to use a foreign key and refer to a new table that stores the history of game types during periods of time? Employees will also learn to deal new games during their career, very rarely they may also have the skill removed.
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Neo4j Specific
With this data would I have an Employee and a Table node that have "isA" relationship edges mapping to actual employees or tables?
I imagine with the skills for the two types I would be best with a Skill node and establish relationships like so?: Blackjack->isA->Skill, Employee->hasSkill->Blackjack, Table->typeIs->Blackjack?
TIME
I find difficulty when I want this database to now work with a timeline. I've come across the following suggestions for connecting nodes with time:
Unix Epoch seems to be a common recommendation?
Connecting nodes to a year/month/day graph?
Lucene timeline? (I don't know much about this or how to work with it, have seen some mention it)
And some cases with how time and data relate:
Staff have varied days and start/end times from week to week, this could be shift node with properties {shiftStart,shiftEnd,actualStart,actualEnd}, staff may arrive late or get sick during shift. Would this be the right way to link each shift to an employee? Employee(node)->Shifts(groupNode)->Shift(node)
Tables and Staff may have skill data modified, with archived data this could be an issue, I think the solution is to have time property on the relationship to the skill?
We open and close tables throughout the day, each table has open/close times for each day, this could change in a month depending on what management wants, in addition the times are not strict, for various reasons a manager may open or close tables during the shift. The open/closed status of a table node may only be relevant for queries during the shift, which confuses me as I'd want this for queries but for archiving with time it might not make sense?
It's with queries that I have trouble deciding when to use a node or add a property to a node. For an Employee they have a name and ID number, if I wanted to find an employee by their ID number would it be better to have that as a node of it's own? It would be more direct right, instead of going through all employees for that unique ID number.
I've also come across labels just recently, I can understand that those would be useful for typing employee and table nodes rather than grouping them under a node. With the shifts for an employee I think should continue to be grouped with a shifts node, If I were to do cypher queries for employees working shifts through a time period a label might be appropriate, however should it be applied to individual shift nodes or the shifts group node that links back to the employee? I might need to add a property to individual shift nodes or the relationship to the shifts group node? I'm not sure if there should be a shifts group node, I'm assuming that reducing the edges connecting to the employee node would be optimal for queries.
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If there are any great resources I can learn about database development that'd be great, there is so much information and options out there it's difficult to know what to begin with. Thanks for your time :)
Thanks for spending the time to put a quality question together. Your requirements are great and your specifications of your system are very detailed. I was able to translate your specs into a graph data model for Neo4j. See below.
Above you'll see a fairly explanatory graph data model. In case you are unfamiliar with this, I suggest reading Graph Databases: http://graphdatabases.com/ -- This website you can get a free digital PDF copy of the book but in case you want to buy a hard copy you can find it on Amazon.
Let's break down the graph model in the image. At the top you'll see a time indexing structure that is (Year)->(Month)->(Day)->(Hour), which I have abbreviated as Y M D H. The ellipses indicate that the graph is continuing, but for the sake of space on the screen I've only showed a sub-graph.
This time index gives you a way to generate time series or ask certain questions on your data model that are time specific. Very useful.
The bottom portion of the image contains your enterprise data model for your casino. The nodes represent your business objects:
Game
Table
Employee
Skill
What's great about graph databases is that you can look at this image and semantically understand the language of your question by jumping from one node to another by their relationships.
Here is a Cypher query you can use to ask your questions about the data model. You can just tweak it slightly to match your questions.
MATCH (employee:Employee)-[:HAS_SKILL]->(skill:Skill),
(employee)<-[:DEALS]-(game:Game)-[:LOCATION]->(table:Table),
(game)-[:BEGINS]->(hour:H)<-[*]-(day:D)<-[*]-(month:M)<-[*]-(year:Y)
WHERE skill.type = "Blackjack" AND
day.day = 17 AND
month.month = 1 AND
year.year = 2014
RETURN employee, skill, game, table
The above query finds the sub-graph for all employees who have the skill Blackjack and their table and location on a specific date (1/17/14).
To do this in SQL would be very difficult. The next thing you need to think about is importing your data into a Neo4j database. If you're curious on how to do that please look at other questions here on SO and if you need more help, feel free to post another question or reach out to me on Twitter #kennybastani.
Cheers,
Kenny
I am planning on creating a database to track user's time in/time out M-F. Every week should begin on monday and run through sunday.
I have a table filled with my entire user population, so I know which users I need to create entries for and where they belong to. I have proposed so far, a table consisting of the following fields to track the entries (along with example data to fill the fields):
Field Name in table (Example of possible data)
---------------------
Employee (John Smith) 'String
Unit (Quality Assurance) 'String
WeekOf (9/9/13) 'date
InMonday (6:30) 'string, validate either a time in/out or N/A if holiday/vacation
OutMonday (3:15) '^^
HoursWorkedMonday (8.00) 'total hours worked
VacationMonday (0.00) 'if N/A for time, should have hours here
OvertimeMonday (0.00) 'any additional work hours should go here
For this instance, I would have to create In/Out for each day of the week (and perhaps track the date that each day is for). Is this extraneous or is there a seemingly better organization to tracking weekly time measurements? Should I use one table with a unit indicator or multiple tables for each unit?
Usually it's one table with a Date field, an In field and an Out field. That's pretty much standard timesheet data. Take a look at how this guy has it set up.
Make sure you're using an Employee ID in the timesheet, and then you would have a corresponding Employee table with all relevant info (ID, Name, Address, whatever else you store on him/her).
While this project is technically feasible, I have to question the value of making it yourself in Access.
The main issue is with security:
As a desktop program, this can be very easy to hack without precautions. Keep in mind that with Access, the user interface and the designer interface are by default the same thing.
If this is going to be a simple, straightforward db, a motivated user just needs to open the navigation panel and they can add/edit/delete all the timesheets.
If you hide the navigation panel, the user can just do a quick google search and learn to hit F11 (or find it by accident, either way)
You can try regularly (daily? hourly?) transferring the data from the publicly accessible back-end to an archive db that is not accessible to the general users. This can work, but still gives them a window to edit records. And if you don't do the transfer right, they can still add old records.
As a webform on a SharePoint, this can be fairly secure. I'd recommend this if you have Sharepoint.
You should also consider your development time. This is a very common business task across many industries, from restaurants to factories to schools. As such, there's a huge number of cheap web-based options already out there that you can start using today. I'll even assume some of these include summary reviews breaking out numbers by departments as well.
I've never researched these myself, but a quick google search found this interesting page: http://en.wikipedia.org/wiki/Comparison_of_time_tracking_software