ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Setting Up a MYSQL Database - AJAX and the Graphing Calculator - Part 5 in a series

Updated on August 23, 2012

Create the Database

A diversion from Javascript into database land

This series is about programming Javascript, but this particular Hub is about setting up a database, because I need a flexible and efficient way to store data that my javascript code is going to use. In the previous Hubs in this series, I introduced a Web application which will track users' locations over time so that user's can find other geographically compatible individuals. I called this application, Geomatch.

Geomatch is admittedly, a gross over-simplification of a Web application. I am basically just using it to explain a few basic principals. I promise, I will get back to javascript in another Hub or two, but javascript doesn't exist in isolation, and this behind the scenes diversion is useful to explain the larger context that javascript applications exist in.

MySQL is a relational database. Information in relational databases is stored in tables, and the power of the database comes from its ability to sort, merge and select items from tables. It is a different paradigm for manipulating data than the loops and branches of a programming language. A full explanation is a voluminous topic in its own right. I just need a place to store the data for geomatch, and I will explain the tables I created for that purpose.

The first step is to create the named database where I will store my tables. The screen shot to the right, illustrates.

For the purposes of my application, there are two entities of interest. Namely, users, and visits to locations made by those users.

Create a User Table

Details about the user table

My user table just has two columns in it, an Id and a string for storing the display name of the user. A real application would need to store much more: passwords, account status, secret questions, etc. However, since I am just illustrating the ideas, I can dispense with all that. The id will be used for efficiently relating the user with rows from the visit table. The name will be used for interactions with the user interface. Users will use this string to identify themselves and each other.

Because both the id and the name will be used for look up, I also created an index for each of these columns.

AUTO_INCREMENT is a convenient way to create unique ids.

It would be confusing if the same user name could be associated with more than one id. So, I used the UNIQUE keyword to prevent this.

Create a Visit Table

Details about the visit table

A visit consists of who was where, when. I have used Cartesian coordinates (x and y) to simplify the mapping to graphs made by the graphing calculator. A real application would probably, use longitude and latitude internally, present users with maps that allowed graphical input of their location, and transform the data before presenting it to the code that renders the results. I'm not bothering with all of that, all three contexts, input, internal representation, and display output will use the same, simple x and y coordinates.

Who has to be a user that is known to my application. The FOREIGN KEY keyword enforces this. Visits will be searched by who and when. So, I created an index (KEY) that will be efficient for doing that.


    0 of 8192 characters used
    Post Comment

    No comments yet.


    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at:

    Show Details
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)