There are many databases. To understand what they are, it is necessary to consider their contents. But there is one small useful detail - metadata. This is what summarizes all the information available. What were they designed for and why are they used?
What is metadata?
It should be noted that there is no single formulation of this concept. So, metadata is a general name for information about a database.
Mainly four designations of this term are used:
- May imply sub-channel information about the data used.
- This is the name of the characteristics that describe the essence. They are needed to look up, identify, evaluate and manage values in the database. It also refers to an important set of a certain number of structured descriptions provided in a valid form and explicitly available, so that you can find the necessary object. This wording is used in cases where it is necessary to search for entities, resources and objects.
- Data from a common formal system that describes the properties of a particular information store.
- Information about the characteristics of the web page (when it was created, who is its author).
The difference betweendata and metadata
How are they different? The fact is that it is usually impossible to make an unambiguous division. Why? Let's take a closer look at an example:
- Something can play both roles. For example, the title of an article can be considered both as a metadata element and as information that is passed to the reader.
- The ability to change places. Let's say someone wrote a poem. It represents data. The composer, relying on the words, created a musical composition and attached this text. In this case, it turns into metadata. It all depends on the use. In general, such cases are possible due to the perception of a certain point of view based on one's judgments (namespace and frame of reference play a role here).
- The ability to create meta-…-metadata based on the axiom of choice. This follows from the fact that almost any information can have its own system of characteristics.
Metadata of files in computers
They have also found their way into automated workflows. If a program is able to work with the content and data structure, then they can be converted to another type of information, which allows users to free themselves from many inconvenient and routine actions.
An example is developments that allow you to view graphic images with different extensions. You can also think of various sound recordings, films and many other things.
Metadata on the World Wide Web
On the Internet, they are used to search for the necessary useful information among huge amounts of data. From this point of view, manually created metadata is of great value because of its meaningfulness. Key words, tags and a number of other elements can act as this type of information. Metadata is what briefly tells about the site. When analyzing several sites by search engines, if they identify the same thematic words on them, then their mutual indication to each other will be more important than from ordinary sites.
How are they distinguished? Basically, the classification is carried out according to one of two principles:
- Content. Metadata is used to describe a file, resource, or its contents (for example, the title is "how to cook potatoes").
- According to belonging. Metadata can be used to inform about something as a whole or its component. Thus, the title of the movie refers to the whole of it, while the description of the episode only informs about a certain part.
If metadata is a set of dependencies on inference capabilities, then in this case they are divided into 3 types:
- "Raw" data. The basis of information support.
- Metadata describing the content. They, in turn, are also used.
- Metadata that can be used to draw a logical conclusion.
Such types of metadata exist.
Three most requestedclass
Let's take a look at three classes that are now widely used:
- Internal metadata. This is information that describes the constituent parts of things, their structure and what it is. An example is the file size and format.
- Administrative metadata. Required for information processing processes, as well as for assigning things. For example, who is the author, editor, when the file was created.
- Descriptive metadata. Used to characterize the nature of the file and its features (which category it belongs to, what else it is associated with).
This is the name of a standard that is used to formally describe some category of resources (entities, objects, etc.).
Usually it has a certain set that characterizes the object in question. For this, attributes, properties, metadata elements are used. Classified by the scope and details of the described resources.
When might a metadata error occur? Lack of necessary information or limited access are the main causes of problems.
Also, a metadata loading error appears in cases where the file exists, but it is damaged. There are three main reasons for this state: wear and tear of equipment, the harmful effects of individual programs (usually computer viruses) and incorrect completion of work with a document, due to whichdata was saved incorrectly.
Accordingly, the value of metadata in the classification and systematization of network information is difficult to overestimate. Therefore, those who wish to optimize their own site simply need to know about them.