The simplest databases can be created using ordinary text editors without the use of specialized software. The main thing is that the data should have a clear structure and the contents of the fields should be easily distinguishable. Such databases are suitable, for example, for lists of employees, card numbers or customers who are members of a loyalty program. Most often these are small amounts of data.
Text files
Information in text formats (txt, csv), where fields are separated by spaces, tabulation and punctuation marks: commas, semicolons and colons. The simplest databases are suitable when you need a simple database that contains 50-200 records. For example, for a telephone directory.
Advantages:
- can be edited with an ordinary text editor;
- it is convenient to work with configuration data.
Disadvantages:
- difficult to establish relationships between data;
- not suitable for large amounts of data.
Examples: etc/passwd and etc/fstab, csv files, ini files, and others.
Hierarchical
A hierarchical database is a system with a root directory and a hierarchy of subdirectories and files. All objects are divided into ancestors and descendants and are closely related. Each record can have no more than one ancestor, so the database has a tree structure. Hierarchical databases are suitable, for example, for creating the organizational structure of a company.
Advantages:
- the path to an object is constructed from the names of root and subdirectories;
- subordination relations can be modeled.
Disadvantages:
- The data storage system is limited.
Examples: file systems, DNS and LDAP.
Networked
Network databases are similar to hierarchical databases, but they can have more than one parent. This allows complex relationships between objects to be modeled. Huge amounts of information on the Internet, where hyperlinks link millions of documents, are organized in this way.
Example: IDMS.