What is meant by a Relational Database Management System?

Answer 1

A "Relational Database Management System" (RDBMS) is a method of arranging data records such that they have something in common with each other (i.e., they can "relate" to each other in some way) and can be easily accessed in a meaningful way to the person examining that data. A simple RDBMS is a hand-written shopping or to-do list, which may include groceries and/or clothing and/or pet needs and/or stop at a bank and/or doctor's office visit, etc. Although the listed items - - which can be construed as database records - - may have nothing to do with each other, per se, they are all related in that they need to be obtained by the person who wrote the list. In this case, the piece of paper they are recorded on would be considered the "database" (i.e., no computer is necessary), and which might be arranged alphabetically and/or by retailer and/or location, etc, though, in this case, a sequential order of some kind, isn't necessarily important. More complex examples of an RDBMS would be an accountant's spreadsheet of a client's income and expenses, or an insurance agent's actuarial tables, or a telemarketer's "call" list. Typically, such "databases" consist of a variety of information about multiple individuals, include people's names, addresses, phone numbers, e-mail addresses, birthdates, etc. Due to the potentially high number of records, a special computer program might be required to record and sort the data. It is up to the programmer (i.e., the person managing the RDBMS) to code the software (usually utilizing a "Structured Query Language" (SQL)) such that the RDBMS's user (i.e., given the aforementioned list, that would be the accountant, insurance agent, or telemarketer, respectively) can arrange, display, print, and/or use it in a meaningful way (i.e., the user might want lists sorted alphabetically by name and/or city and/or state, and/or numerically by phone area code, etc). A far more complex RDBMS would be used by local, county, state, or national governments, in order to maintain hundreds, thousands, or millions of records on citizens for a variety of purposes, including education, health, security, social welfare, criminal backgrounds, income taxes, etc. Again, both the breadth and complexity of the records would require a well-designed database.