Search And Grading Technologies
Launch of the " Informatics Examination " 11th Class , [Informatics Equivalence][Bylet No. 21]
Every one of us, from early childhood, has faced multiple "databases." It's all possible directories, encyclopedia... The notebook is also a databank that each of us has.
Databases are information models containing site data and properties. Databases store information on objects with the same properties. Database information is kept in order (e.g., in the notebook, all records are arranged in alphabet, in the library catalogue, either alphabetically or in the field of knowledge).
Database - This is an information model that allows for the orderly storage of data on a group of objects with the same set of properties.
There are several different types of databases: tabular, hierarchical and network.
Table databases.
The database contains a list of objects of one type, i.e. objects with the same set of properties. This database is easily presented in a two-way table.
See, for example, the Compewter (Table) database, which is a list of facilities (computers), each of which has a name. The type of processor and the extent of operational memory may be characteristic(s).
The table ' s table is referred to as the fields; each field is marked by its name (name of the relevant characteristic) and the type of data reflecting the values of the characteristic. Field Name and Type of Processor are textual, and Operational memory is number. At the same time, each field has a set of properties (dimension, format, etc.). For example, a complete number of data formats are given to the field of Operational memory.
The field of the database is a column of the table that includes the values of a certain characteristic.
The plots are site notes; these records are broken down on the poles of the table. The database is a line of the table that contains a set of values of the different properties of the object.
Each table shall have at least one key field which is unique to any record in this table. The key field values clearly define each entry in the table.
