Data hierarchy is the hierarchical grouping of data, in which one piece of datum leads to a layer of data, which leads to another layer under that. Each layer gets more specific, until the user finds exactly what he or she wants. Aside from helping the user find information, it also is used to create correct responses from programming languages based on user input. Data hierarchy is most often used to catalog data in databases, but it also is found in other programming schemas.
In data hierarchy, all data have their own hierarchy, starting from a broad top level and working through to a specific bottom level. For example, someone wants to find a video game title in a database. The hierarchy starts with the video game console type, then the game developer, then the genre, the starting letter of the game name and, finally, the game itself. Cataloging data in this way makes it easier to find. It also makes it easier on the database when new information is added by ensuring that datum is only entered in the correct category.
While all databases have a data hierarchy, they are usually programmed in different ways depending on the database model. For example, in the hierarchical database model, the administrator has to insert each piece of datum into either a parent or child node. The parent is a broad category, while the child is the table that comes after the parent. In the relational model, data are related to one another so, when someone selects one table, related tables will appear.
By placing data in separate hierarchies, it makes it easier to add to the database or programming language. If the programmer wants to add a new video game made for one console to the video game database, it can be difficult to organize, because the game developer often works with several different consoles at once. By following the hierarchy, he or she will know exactly where to place this new data.
Programming languages also use data hierarchy, but in a different way. With programming languages, the driving force is user interaction. The program may ask the user what he or she is looking for, or what his or her preferences are. The hierarchy will tell the program to react in a certain way or to open a branch of data, depending on what the user clicks or enters. Data hierarchy, in this regard, is usually split into different programming objects, so each hierarchy is its own encapsulated unit.