Information, being the basis for the work of variouselectronic data exchange systems, is organized in a special way and is called databases. To understand this concept, and also to understand what the structure of the database is, it is worthwhile to consider this phenomenon in more detail.
Most often, when creating a database, you shouldadhere to the following requirements. It should be easy to process and be compact, devoid of redundant information. In a hierarchical system, the elements are arranged in such a way that relationships are formed between them - the child and the parent. That is, this information is located above or below with respect to a certain object of the system. But one of them is always the main one, from which the entire system begins. As a result of this arrangement of information blocks, a tree structure of the database is formed, which is typical for the file system applicable in computers.
The databases distributed on the network have the same characteristics as hierarchical databases. The difference between them is that in the first child elements can have several ancestors.
But before we consider the structure andtypes, you need to define the concept of a database. What is meant by this term? The simplest definition is this: a database is a way of organizing and storing information. There are many kinds and ways of organizing information. Each of them has its own target orientation, meets certain requirements. For example, data in the XML language is structured as a tree that has a branched root and nodes. But this is only one of the types of information storage.
Hierarchical structure of the databaseoptimized for reading, quick data selection and output to the user. But it has its drawbacks. So, the computer, quite easily performing the operation with a specific folder or file (which are elements of the hierarchical structure), for a long time is engaged in checking the system for viruses. This shows that such a system is not suitable for quickly scanning information and, if necessary, the process takes a long time. The relationship of elements in a similar structure is such that the lower the object is, the greater its nesting. The hierarchical relationships between the parent and child elements of the system are affected.
Another classification of bases deserves attentiondata. It will be introduced in order to finally clarify the issue of the existing ways of storing information. By the nature of the submission of information, the databases are divided into structured (data in the form of symbols), partially structured (textual information) and unstructured (semantic networks). Structured databases have several levels on which information units are located. These include network and hierarchical databases, where separate files are assigned links. If the hierarchical database is similar to a tree, then the network looks like a network. In this case, the structure of the database is arranged in such a way that any vertex can lead to it and there can be several links between a pair of vertices. So, one file maintains relations with many, as a result of which its type is not fixed. It can be a member of a set of files (between which a link is declared) or the owner.
There is also a relational database model, in whichThe links between files are dynamically determined at the time the request is executed. Databases are divided according to the type of information contained in them, on factographic, documentary and lexicographic.
Thus, databases are in a special waystructured system, one of the ways of storing information in which there can be a tabular form. The collection of several tables that have logical connections to each other, and create a database.</ p>