As a paranoid entry-level developer I was wondering if it is possible for a user to use some kind of query to insert data into a database through a form with a select field.
More specifically lets say in my db I have a Gender column (data type text) and in my form I am using the select tag and passing in 2 options Male and Female. Although in the html the user only has 2 options to select from but the db doesn't know that. The gender column will pretty much accept anything. I just wanted to know if a nuisance user can disregard the select options and somehow insert a silly answer into the Gender column? If so, how can I protect from that.
The thing you are talking about here is the validations need to be done before entering data to the database. Invalid data can come from anywhere ( directly from controller or from GUI) and its the responsibility of the model to validate the data before it commits to the database.
Go through these links.
http://api.rubyonrails.org/classes/ActiveRecord/Validations.html
http://guides.rubyonrails.org/active_record_validations_callbacks.html
Related
This is complicated and difficult to explain, but here it goes. I have created a db that works just fine. It is a time saver, but not efficient for the user. I have a form for the merchandise where the user selects a paper type from a combobox. They are presented with two choices. They must also select a print size from another combobox. They are presented with 5 choices. I have VBA code that creates a SKU number based on these selections.
An art piece can use both paper types and be available in all 5 sizes. What I am trying to figure out is how I can offer all the possible choices on this form, allow the user to select options for that piece. As an example, the user chooses both paper types and all print sizes. This would create 10 SKU numbers for one art piece. Below is a copy of the form in it's current view:
Is this possible to do from one form? If so, how can this be accomplished in the most efficient way? I feel that it can. In VBA, this would be an IF nest nightmare, especially when concatenating the SKU variables. Either Select statements or another method that I am unaware of, could be the solution.
Thanks in advance for any and all suggestions and assistance.
EDIT: I hope this helps clarify. I would prefer to use this form
to complete the task. The checkboxes are not in an option group so they could all be checked if the user requires it. For the purposes of this question, let's assume the user has checked all the boxes. This would equal 10 total combinations.
I run this sub to generate a SKU based on the paper type and the print size:
Private Function UpdateArtwork()
Me.MerchandiseSKU = Me.cboArtworkID_A5A.Column(5) & _
Me.cboPrintTypeID_A5A.Column(2) & Me.cboPaperTypeID_A5A.Column(0) & _
Format(Me.cboPrintSizeID_A5A.Column(0), "00")
Call UpdateArtworkPic
End Function
I am trying to figure out how to write the code for the new form that allows all 10 SKU numbers to be generated and create 10 new records for Artwork_ID (Artwork table).
I think that the best way of doing this would be to create a new table, called tblArtworkSKU, which has the following fields:
ArtworkSKU_ID - Autonumber, primary key;
Artwork_ID - number, foreign key from the Artwork table;
PrintSize_ID - foreign key from the PrintSize table;
PrintType_ID - foreign key from the PrintType table;
ArtworkSKU - text.
You would then create a small continuous form based on this table, with PrintSize_ID and PrintType_ID selected through combo boxes. When you place this form onto the main form that you have, Access should automatically let you join on Artwork_ID to create a one-to-many relationship.
You could then use the AfterUpdate events of each combo box to create the SKU.
Regards,
In my app does I need to have separate forms for:
Form for showing data i grid
Form for insert
Form for update
Or I just need two: one for displaying data, and one unique for insert and update.
In unique insert form just pass selected id from row and with query load it in fields. First in insert form will declare boolean variable like editMode false. If passed id exist in db activate query and fill fields with values.
Is this good or bad practice? How big companies or skilled developers separate this?
I don't need someone to write code for me. I just want to know proper algorithm for this. Thanks
I'm busy with a rails 4/postgres project that is structured in such a way that requires dozens of fields for a specific object, this being company. Each company would include fields for eg name, location, header_bg, logo, contact name, contact cell etc so the fields very well could grow in the future. What is the best way to structure this DB.
The way I see it I have 3 options:
1) company table with all these fields in the same table
pros: simple, data all in one place and easy to query
cons: table could get very messy and requires manually editing table structure every time a new field is required
~~~~~~
2) company table with an additional company_options table a foreign key company_id. This table will also hold multiple fields
pros and cons are same as above except this will be more neater structure. Crucial data such as company name will go in company table, other data like location, theme, header_bg etc would go in company_options
~~~~~~
3) company table and a company_meta table. This will follow the Wordpress structure of the post_meta table. So it would have the fields: company_id, meta_key, meta_value. each field would go in its own row
pros: flexible, able to dynamically add options/fields without editing table structure
cons: not a simplistic approach with same data in same columns. would need to custom build this functionality for inserting, updating, validation displaying of data. Unless Rails has such a gem which I can't find?
~~~~~~
Any suggestions or additional options would be appreciated. Are there any rules of thumb for determining the kind of structure needed? I started out with the 1st option out of a matter of simplicity but then started to build the 3rd and the amount of code just didn't seem right for what seems like such a common need.
Thanks!
Plan your database schema for the future:
Will a company be able to have several phones?
For repeating information, use a new table:
rails g model phone number:string type:string
rails g migration add_company_id_to_phones company:references
This way you can add several phones and navigate your database to get each phone.
Will your field only have one of a kind?
For example, you might only need one name field for each company. If this is the case, add it directly to the companies table:
rails g migration add_fields_to_companies name:string
Is your data completely optional? Is it unstructured?
Add a JSONB field to your table, assuming you are using Postgresql:
rails g migration add_details_to_companies details:jsonb
With JSONB data type you can use unstructured data like this:
Company.create({
name: "AwesomeCompanyCorp",
details: {
"main phone": "000-0000-0000",
"secondary phone": "000-0000-0000",
"support email": "support email",
"location": "Main Avenue 165",
"latitude": "22.330213123",
"longitude": "60.000012312"
}
})
With JSONB you are able to have unstructured data, but be able to query the field like this:
Company.where("details->>'main phone' = ?", "000-0000-0000")
With this on mind, choose the best approach that fits your case.
I have a rails application linked to a database table, which contains e-mail addresses and passwords. I would like to create a unique number which will identify each of the users in the system. This number will be given to a user upon registration, and stored in the field user_id on the same table.
So, for example, john#foo.bar could get 0001 as an ID, martha#foo.bar could get 0002, and so on.
My question is: what is the best way to do this?
Should I seed the database (rake db:seed) with the first user_id (0001) and write a method in the controller to +1 the user_id every time? If that is the case, how can I access the last row in order to find out the last user_id?
An alternative way would be to find the largest user_id in the table and +1 it. For that I guess I need to use tablename.find_by_user_id or something similar (would tablename.find_by_user_id.max work?)
A third way would be to store the latest user_id somewhere, and have the application retrive it when needed. Where could this information be stored?
I'm very new to rails . Would appreciate your feedback about which is the best way to go.
Thanks,
TimmyOnRails
Lets assume your model has two attributes name and email. Now by default rails will generate three more columns for you
1 id - auto incremental
2 created_at and updated_at - timestamps
Rake db:seed is one of the good solution in case you want to prepopulate the database. All you need to worry about is name and email. Add proper validations for these attributes. Rest rails will handle ie id is maintained by rails itself. You don't need to worry about it. Created_at and updated_at columns are also maintained by rails.
If you new to rails then I will suggest you to check http://railsforzombies.com and that will you a good idea about active records
Railsguides and RailsCasts are also two other learning materials for rails.
Hi iam new in dynamo db and, with my knowledge its a non relational db ie we cant join the tables. My doubt is how we design the table structure. Please clarify with following example.
I have a following tables
1) users - user_id, username, password, email, phone number, role
2) roles - id, name [ie admin, supervisor, ect..]
a) My first doubt is we have any provision to set auto increment for user_id fields ?
b) Is this correct way of setting primary key as user_id?
c) Is this is the correct method to store user role in dynamo db? ie a roles table contains id and title and store role id in user table?
e) Is this possible to retrieve two tables data along with each user? Am using rails 3 and aws-sdk gem
If anybody reply it will be very helpful for me like a new dynamodb user
Typically with nosql style databases you would provide the unique identifier, rather than having an auto increment PK field do that for you. This usually would mean that you would have a GUID be the key for each User record.
As far as the user roles, there are many ways to accomplish this and each has benefits and problems:
One simple way would be to add a "Role" attribute to the Users table and have one entry per role for that user. Then you could grab the User and you would have all the roles in one query. DynamoDB allows attributes to have multiple values, so one attribute can have one value per role.
If you need to be able to query users in a particular role (ie. "Give me all the Users who are Supervisors") then you will be doing a table scan in DynamoDB, which can be an expensive operation. But, if your number of users is reasonably small, and if the need to do this kind of lookup is infrequent, this still may be acceptable for your application.
If you really need to do this expensive type of lookup often, then you will need to create a new table something like "RolesWithUsers" having one record per Role, with the userIds of the users in the role record. For most applications I'd advise against doing something like this, because now you have two tables representing one fact: what role does a particular user have. So, delete or update needs to be done in two places each time. Not impossible to do, but it takes more vigilance and testing to be sure your application doesn't get wrong data. The other disadvantage of this approach is that you need two queries to get the information, which may be more expensive than the table scan, again, depending on the quantity of records.
Another option that makes sense for this specific use case would be to use SimpleDb. It has better querying capability (all attributes are indexed by default) and the single table with roles as multi-valued attribute is going to be a much better solution than DynamoDB in this case.
Hope this helps!
We have a similar situation and we simply use two DBs, a relational and a NoSQL (Dynamo). For a "User" object, everything that is tied to other things, such as roles, projects, skills, etc, that goes in relational, and everything about the user (attributes, etc) goes in Dynamo. If we need to add new attributes to the user, that is fine, since NoSQL doesn't care about those attributes. The rule of thumb is if we only need something on that object page (that is, we don't need to associate with other objects), then we put in Dynamo. Otherwise, it goes in relational.
Using a table scan on the NoSQL DB is not really an option after you cross even a small threshold (up to that point, you can just use an in memory DB anyway).