As a way to score points for the study I’m doing, as well as out of interest into databases and wanting to help my team I’m trying to build a capacity planning tool in MS Access 2007. I work in a department that handles registering and supporting tenders. I have attached two pictures of what I’m trying to do here.
I’ve already spent some weeks making multiple iterations with colleagues who are involved and help write VBA and SQL (out of interest, wanting to learn something or otherwise. Our core business, however, isn’t developing). The primary goal of the database is as follows:
A user can access, create and modify “cases” that correlates to a case ID that we use in a different system.
A user can write down his capacity per week per year for a case.
multiple users can assign themselves to a case.
Users can leave messages (records) for other users to see on a case
Metadata can be attached to the case
The main problem we seem to be running into is that whenever a user tries through to edit an existing case through the overview, the case data no longer “complies” with entries elsewhere. Forcing updates through visual basic also seems to not have worked so far.
Adding to the complexity: most of the names we use are in dutch.
Here is an overview of the relations.
http://imgur.com/O022LAG
Here is a screenshot of the case overview as seen by a user.
http://imgur.com/kuENqaq
Main question:
How can I make entire records change for multiple users based on the input of one user.
In compliance with the guidelines regarding asking subjective questions I’m trying to be a bit more precise here:
Additionally I’m uncertain:
whether it is our approach that is wrong,
if perhaps we’re overlooking a glaring issue, or
if we should redesign this from scratch with a different layout.
Any help specifying where we should look or what would be advisable to do would be much appreciated!
Kind regards,
Timo
I asked the following question on a database site:
I am trying to build an EER Model for a Autostore that has 5 locations
and offers a range of auto products. They offer car repairs and
roadworthy tests as a service also. I need to be able to make
fortnightly reports on unfinished service jobs, and fortnightly
reports on the sales. They have a wide customer database filled with
full addresses. There is a constant inflow of new stock items and
restocking of old ones. There should also be a way to know the cost of
each item in stock and where its being held.
I swear I've researched it enough to be able to understand it by now
but Im really struggling to map this out as I'm constantly running
into a wall when dealing with the products that are being restocked,
sold and stocked by particular stores in different locations.
-I'm a total rookie with this kind of thing but if anyone can help me it would be amazing.
but I am struggling to find an answer and was thinking that maybe if I asked someone here to build an SQL setup it would lead me in the direction of being able to make the model or if there was a way of building the relational model then it would be a simple step from there, unless someone has the original answer - or all of them haha, hope you can help!
Thanks,
Jacob
If you are struggling with creating an EER diagram, my guess is that you may not have captured detailed enough requirements for the application. A clear understanding of the functionality the application should provide should lay the groundwork for what you need to model in the database.
Ask yourself these questions.
Have I created user profiles for each type of user the application will be used by?
Have I outlined every action these users will be performing on the application and the details of the actions?
These are just two of many questions that you have hopefully fully addressed. If you have addressed these topics and everything else fully, perhaps you just need a different approach in organizing your requirements.
Break it up into segments of data. For example, you'll need to create a system of tables that manages inventory. Which will need to then be linked up to a system of tables that manages sales and service records. Which will need to be linked to a system of tables that manages customers data. The sales/service and inventory control will need to be linked up to a system of tables that governs employees and their roles and ability to do things (security, privileges, etc). I can go on and on speaking theoretically about this, but this should hopefully be enough to get you started.
Good luck.
So for my software engineering course, as a part of the larger project, we need to implement a database using HSQLDB. Unfortunately, I haven't taken database design yet, and 3 out of 5 people in our group have dropped the course, leaving this part for me to do.
As of now, I've come up with this ER Diagram for our project:
What we have is a list of courses, and each course contains many modules. Every account can be registered in any course, giving them access to each module of the course, which is graded, and than the mark is stored on their account.
I think the diagram I've come up with represents this fairly well; however, I just started learning about this today, so I'm still a bit shaky, so to say.
Is there anything that jumps out as wrong about this, or parts that could be improved?
P.s - I just noticed in the module table, it contains grade, which should actually be in module_grade.
Course_grade table is absolutley useless in your model. You should store the grade information inside course_grade and module_grade instead of the module directly. Think of module as master data (so something you want to use for all students) which means that you should not store student specific information inside it.
I would also add timestamps to your model at least inside the tables that have the grade information so that you can at least check when the student got the information. If you also have the information available who gave the grade you should probably store that as well.
If you are using SQL to access your model think about changing the foreign key columns in course_grade and module_grade to something that is unique. This makes queries much more readable imo. Maybe for course grade renaming course_id to cg_course_id.
I’ve found multiple questions on SO and elsewhere that ask questions along the lines of “How can I index and then search relational data in Lucene”. Quite rightly these questions are met with the standard response that Lucene is not designed to model data like this. This quote I found sums it up…
A Lucene Index is a Document Store. In a Document Store, a single
document represents a single concept with all necessary data stored to
represent that concept (compared to that same concept being spread
across multiple tables in an RDBMS requiring several joins to
re-create).
So I will not ask that question and instead provide my high level requirements and see if any Lucene gurus out there can help me.
We have data on People (Name, Gender, DOB, Nationality, etc)
And data on Companies (Name, Country, City, etc).
We also have data about how these two types of entity relate to each other where a person worked at the company (Person, Company, Role, Date Started, Date Ended, etc).
We have two entities – Person and Company – that have their own properties and then properties exist for the many-to-many link between them.
Some example searches could be as follows…
Find all Companies in Australia
Find all People born between two dates
Find all People who have worked as a .Net Developer
Find all males who have worked as a.Net Developer in London.
Find all People who have worked as a .Net Developer between 2008 and 2010
The criteria span all the three sets of data. Our requirement is to provide a Faceted Search over the data that accepts any combination of the various properties, of which I have given some examples.
I would like to use Lucene.Net for this. We are a .Net software house and so feel slightly intimidated by java. However, all suggestions are welcome.
I am aware of the idea that the Index should be constructed with the search in mind. But I can’t seem to come up with a sensible index that would meet all the combinations of search criteria
What classes native to Lucene or what extension points can we make use of.
Are there are established techniques for doing this kind of thing?
Are there any third open source contributions that I have missed that will help us here?
For now I won’t describe the scenarios we have considered because I don’t want to bloat out this question and make it too intimidating. Please ask me to elaborate where necessary.
To store both companies and people in a single index, you could create documents with a type field that identifies the type of entities they describe.
Birthdays can be stored as date fields.
You could give each person a simple text field containing the names of companies that they worked for. Note that you won't get an error if you enter a company that is not represented by a document in your index. Lucene is not a relational DB tool, but you knew that.
(Sorry that I've not posted any links to the API; I'm familiar with Lucene Core but not Lucene.NET.)
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(Note: I realize this is close to How do you document your database structure? , but I don't think it's identical.)
I've started work at a place with a database with literally hundreds of tables and views, all with cryptic names with very few vowels, and no documentation. They also don't allow gratuitous changes to the database schema, nor can I touch any database except the test one on my own machine (which gets blown away and recreated regularly), so I can't add comments that would help anybody.
I tried using "Toad" to create an ER diagram, but after leaving it running for 48 hours straight it still hadn't produced anything visible and I needed my computer back. I was talking to some other recent hires and we all suggested that whenever we've puzzled out what a particular table or what some of its columns means, we should update it in the developers wiki.
So what's a good way to do this? Just list tables/views and their columns and fill them in as we go? The basic tools I've got to hand are Toad, Oracle's "SQL Developer", MS Office, and Visio.
In my experience, ER (or UML) diagrams aren't the most useful artifact - with a large number of tables, diagrams (especially reverse engineered ones) are often a big convoluted mess that nobody learns anything from.
For my money, some good human-readable documentation (perhaps supplemented with diagrams of smaller portions of the system) will give you the most mileage. This will include, for each table:
Descriptions of what the table means and how it's functionally used (in the UI, etc.)
Descriptions of what each attribute means, if it isn't obvious
Explanations of the relationships (foreign keys) from this table to others, and vice-versa
Explanations of additional constraints and / or triggers
Additional explanation of major views & procs that touch the table, if they're not well documented already
With all of the above, don't document for the sake of documenting - documentation that restates the obvious just gets in people's way. Instead, focus on the stuff that confused you at first, and spend a few minutes writing really clear, concise explanations. That'll help you think it through, and it'll massively help other developers who run into these tables for the first time.
As others have mentioned, there are a wide variety of tools to help you manage this, like Enterprise Architect, Red Gate SQL Doc, and the built-in tools from various vendors. But while tool support is helpful (and even critical, in bigger databases), doing the hard work of understanding and explaining the conceptual model of the database is the real win. From that perspective, you can even do it in a text file (though doing it in Wiki form would allow several people to collaborate on adding to that documentation incrementally - so, every time someone figures out something, they can add it to the growing body of documentation instantly).
One thing to consider is the COMMENT facility built into the DBMS. If you put comments on all of the tables and all of the columns in the DBMS itself, then your documentation will be inside the database system.
Using the COMMENT facility does not make any changes to the schema itself, it only adds data to the USER_TAB_COMMENTS catalog table.
In our team we came to useful approach to documenting legacy large Oracle and SQL Server databases. We use Dataedo for documenting database schema elements (data dictionary) and creating ERD diagrams. Dataedo comes with documentation repository so all your team can work on documenting and reading recent documentation online. And you don’t need to interfere with database (Oracle comments or SQL Server MS_Description).
First you import schema (all tables, views, stored procedures and functions – with triggers, foreign keys etc.). Then you define logical domains/modules and group all objects (drag & drop) into them to be able to analyze and work on smaller chunks of database. For each module you create an ERD diagram and write top level description. Then, as you discover meaning of tables and views write a short description for each. Do the same for each column. Dataedo enables you to add meaningful title for each object and column – it’s useful if object names are vague or invalid. Pro version enables you to describe foreign keys, unique keys/constraints and triggers – which is useful but not essential to understand a database.
You can access documentation through UI or you can export it to PDF or interactive HTML (the latter is available only in Pro version).
Described here is a continuous process rather than one time job. If your database changes (eg. new columns, views) you should sync your documentation on regular basis (couple clicks with Dataedo).
See sample documentation:
http://dataedo.com/download/Dataedo%20repository.pdf
Some guidelines on documentation process:
Diagrams:
Keep your diagrams small and readable – just include important tables, relations and columns – only the one that have any meaning to understand big picture – primary/business keys, important attributes and relations,
Use different color for key tables in a diagram,
You can have more than one diagram per module,
You can add diagram to description of most important tables/with most relations.
Descriptions:
Don’t document the obvious – don’t write description “Document date” for document.date column. If there’s nothing meaningful to add just leave it blank,
If objects stored in tables have types or statuses it’s good to list them in general description of a table,
Define format that is expected, eg. “mm/dd/yy” for a date that is stored in text field,
List all known/important values an it’s meaning, e.g. for status column could be something like this: “Document status: A – Active, C – Cancelled, D – Deleted”,
If there’s any API to a table – a view that should be used to read data and function/procedures to insert/update data – list it in the description of table,
Describe where does rows/columns’ values come from (procedure, form, interface etc.) ,
Use “[deprecated]” mark (or similar) for columns that should not be used (title column is useful for this, explain which field should be used instead in description field).
We use Enterprise Architect for our DB definitions. We include stored procedures, triggers, and all table definitions defined in UML. The three brilliant features of the program are:
Import UML Diagrams from an ODBC Connection.
Generate SQL Scripts (DDL) for the entire DB at once
Generate Custom Templated Documentation of your DB.
You can edit your class / table definitions within the UML tool, and generate a fully descriptive with pictures included document. The autogenerated document can be in multiple formats including MSWord. We have just less than 100 tables in our schema, and it's quite managable.
I've never been more impressed with any other tool in my 10+ years as a developer. EA supports Oracle, MySQL, SQL Server (multiple versions), PostGreSQL, Interbase, DB2, and Access in one fell swoop. Any time I've had problems, their forums have answered my problems promptly. Highly recommended!!
When DB changes come in, we make then in EA, generate the SQL, and check it into our version control (svn). We use Hudson for building, and it auto-builds the database from scripts when it sees you've modified the checked-in sql.
(Mostly stolen from another answer of mine)
This answer extends Kieveli's above, which I upvoted. If your version of EA supports Object Role Modeling (conceptual design, vs. logical design = ERD), reverse engineer to that and then fill out the model with the expressive richness it gives you.
The cheap and lighter-weight option is to download Visiomodeler for free from MS, and do the same with that.
The ORM (call it ORMDB) is the only tool I've ever found that supports and encourages database design conversations with non-IS stakeholders about BL objects and relationships.
Reality check - on the way to generating your DDL, it passes through a full-stop ERD phase where you can satisfy your questions about whether it does anything screwy. It doesn't. It will probably show you weaknesses in the ERD you designed yourself.
ORMDB is a classic case of the principle that the more conceptual the tool, the smaller the market. Girls just want to have fun, and programmers just want to code.
A wiki solution supports hyperlinks and collaborative editing, but a wiki is only as good as the people who keep it organized and up to date. You need someone to take ownership of the document project, regardless of what tool you use. That person may involve other knowledgeable people to fill in the details, but one person should be responsible for organizing the information.
If you can't use a tool to generate an ERD by reverse engineering, you'll have to design one by hand using TOAD or VISIO.
Any ERD with hundreds of objects is probably useless as a guide for developers, because it'll be unreadable with so many boxes and lines. In a database with so many objects, it's likely that there are "sub-systems" of a few dozen tables and views each. So you should make custom diagrams of these sub-systems, instead of expecting a tool to do it for you.
You can also design a pseudo-ERD, where groups of tables are represented by a single object in one diagram, and that group is expanded in another diagram.
A single ERD or set of ERD's are not sufficient to document a system of this complexity, any more than a class diagram would be adequate to document an OO system. You'll have to write a document, using the ERD's as illustrations. You need text descriptions of the meaning and use of each table, each column, and the relationships between tables (especially where such relationships are implicit instead of represented by referential integrity constraints).
All of this is a lot of work, but it will be worth it. If there's a clear and up-to-date place where the schema is documented, the whole team will benefit from it.
Since you have the luxury of working with fellow developers that are in the same boat, I would suggest asking them what they feel would convey the needed information, most easily. My company has over 100 tables, and my boss gave me an ERD for a specific set tables that all connect. So also, you might want to try breaking 1 massive ERD into a bunch of smaller, manageable, ERDs.
Well, a picture tells a thousand words so I would recommend creating ER diagrams where you can view the relationship between tables at a glance, something that is hard to do with a text-only description.
You don't have to do the whole database in one diagram, break it up into sections. We use Visual Paradigm at work but EA is a good alternative as is ERWIN, and no doubt there are lots of others that are just as good.
If you have the patience, then using html to document the tables and columns makes your documentation easier to access.
If describing your databases to your end users is your primary goal Ooluk Data Dictionary Manager can prove useful. It is a web-based multi-user software that allows you to attach descriptions to tables and columns and allows full text searches on those descriptions. It also allows you to logically group tables using labels and browse tables using those labels. Tables as well as columns can be tagged to find similar data items across your database/databases.
The software allows you to import metadata information such as table name, column name, column data type, foreign keys into its internal repository using an API. Support for JDBC data sources comes built-in and can be extended further as the API source is distributed under ASL 2.0. It is coded to read the COMMENTS/REMARKS from many RDBMSs.You can always manually override the imported information. The information you can store about tables and columns can be extended using custom fields.
The Data Dictionary Manager uses the "data object" and "attribute" terminology instead of table and column because it isn't designed specifically for relational databases.
Notes
If describing technical aspects of your database such as triggers,
indexes, statistics is important this software isn't the best option.
It is however possible to combine a technical solution with this
software using hyperlink custom fields.
The software doesn't produce an ERD
Disclosure: I work at the company that develops this product.