Database Design: An Introduction
Database companies offer a range of services that can cater for all purposes, from small in-house business systems, e-commerce solutions for website, to large scale databases, and can allow for single to multiple simultaneous users. When looking into options ask database developers if they can offer bespoke designs that accommodate your business’s requirements. If you already have a design or technologies in mind, it is still advisable to consult with a database company or database developer who will work with your requirements, or advise you about alternatives that may be more efficient. Also, database consultants will talk you through the models and languages used by designers to create a database. And finally, when planning your database, design it with database development in mind. Aim to create a site that will be adaptable to your needs as your business grows.
What does Database design consist of?
Database design refers to the design of data structures for the storage of data. A database system is made up of different design parts. When designing a database there are certain steps that need to be taken in order to ensure the success of your design. In fact, the design process is the most important part of the database. You will need a requirements specification, which defines not only what data will be available, but also how the data will be stored. These decisions form the Conceptual schema of a database. This means the determination of dependencies between data, or the relationships between data. In other words, one item may depend upon another, but the inverse is not necessarily true.
Databases are a collection of data tables, and each table should have a distinct object. Analyse the fields and find what grouping arise. When the relationships have been determined, the logical structure of the data can be formed into storage objects, supported by the database management system (DBMS). Databases range in complexity, from single-file database, which can store different tables of information but has no way of linking them, to multi-file databases also know as relational database programs (RDMS). These are used in Access database development. Additionally, you can include rules and constraints to the data, and database views and reports, all of which will aid the success of your database.
Relational model: In order to group information, the object to each table of information must be determined. Once this has been established, the relationship between objects creates a relational model. In relational databases, storage objects are tables which store data in rows and columns. Each table should be broken down into the simplest units of data. Every table has a key, which is a column of values that uniquely identifies each row in a table. To link it to another table, a foreign key must be identified in another table, and the link field in another table is the foreign key data field.
So, the primary key in the primary table (parent table) will be related to a foreign key in a related table (child table). Linked tables must have the same name, structure and data type as the primary table. Relationships are stored as links, connecting one or more children tables with parents. From this relational model, a hierarchical parent-child relationship table may be formed. You can also implement a logical object or relationship which can join one or more logical objects, and therefore complex logical relationships may have links with more than one parent.
With Access database design, it is important for you to normalise the data. Normalisation will increase the efficiency of your database, save storage space, and protect against corruption. The steps that must be taken to normalise your data are (as with any relational model) the data must be placed in column and rows, and then a key must be added to your data. Finally check that the table contains only unique data. In other words, each data field has only one item of data, and the table contains data only related to the primary key. Any other data must be removed. You must also ensure that the information in each table is properly linked in order for the relational model to work.
In relational databases, Structured Query Language (or SQL) is used to build and manipulate the model. SQL database design provides capabilities for querying, modifying and managing databases. Call Level Interface is included in SQL, which allows for the remote maintenance of databases.
Object database: In an object database, a one-to-many relationship may be formed, creating a hierarchical relationship. Relationships here are the methods that operate on the object class. Object-orientated programming language is the language used to write the applications that manage and access the data. The storage object relates directly to the objects used by the programming language.
Physical database design: This specifies the actual construction (including data elements, data types, indexing options, other parameters) of the database on the storage media.
