Each software developer has his own way of developing a web application, but a data model is one of the first steps in creating an efficient, streamlined application. When you create a data model, the code falls into place. By creating the data model first, you can ensure that your web application covers all of the requirements needed to build the website.
What is a Data Model?
A data model is a visual representation of your application. It shows each unit or section of the website, and the model includes details that encapsulate a part of the website. For instance, if you have an ecommerce site, you will likely have a section for customers. The data model will have a “customers” table, and this table consists of each property you store for a customer such as name, address, and telephone number.
Data models are taken from specification documents. The models ensure that your application covers all of the customer’s requirements. In large projects, developers can easily forget or miss some requirements, which is devastating for project completion. A missing requirement can mean delays in project completion, an overhaul in the code, and in some cases, cancellation of the project as a whole. If you map out the data model from the specification documentation, there is a reduced chance that you forget some part of the customer’s requirements.
Data Model Associations
After you’ve created models (tables) for each section of the web application, you need to associate the tables, so the data flows throughout the application. An association is a link between two or more tables. For instance, if you have a “customers” table and an “orders” table, you need to link those tables through an association. An association has a primary key and a foreign key. In this example, the primary key is located in the customers table and the foreign key is located in the orders table.
Associations can be one-to-one, one-to-many, or many-to-many. A one-to-one relationship is one where a single record in the primary table links to one record in the foreign key table. For instance, if you have customers with a billing address table, you might only want to allow one billing address. The association would then be one-to-one from the customer table to the billing table.
A one-to-many relationship means a record in the primary table links to multiple records in the foreign key table. A simple example of this type of relationship is a customer and order table relationship. An order can only be linked to one customer, but a customer can link to multiple orders. The association is then a one-to-many from the customer table to the order table.
Many-to-many relationships are more complicated. To normalize a data model with a many-to-many relationship, you want to break up the relationship to a third table. The third table has a primary key and then contains the primary keys to the associated tables. A good example of this type of relationship is an order and product table association. An order can have multiple products associated with it, and products can be linked to multiple orders. You then create a third table that contains the order and product primary keys and link this third table to the order and product tables. This type of breakdown on the model is called normalization.
Data Modeling Tools
Several tools on the market help you create a data model using drag-and-drop visualization procedures. For instance, Visual Studio contains a data modeler for Entity Framework, which is a type of framework used to embed data models in Microsoft MVC web applications. This tool is free with Visual Studio Express versions.
The modeling tool you use should be able to export to the database you want to use. The common databases on the Internet are MySQL, SQL Server and Oracle. MongoDB is slowly gaining popularity, but MongoDB is a “NoSQL” database used for big data queries and storage. The modeling tool should be able to take the model you created and create a database from it.
Data modeling is an important part of web development, and creating a good model will guide you through the UI process and make your code more efficient. Always start your project with a database model to avoid making messy coding mistakes.