Query-by-E~ample"~ is a high-level data base management language that provides a convenient and unified style to query, update, define, and control a relational data base. The philosophy of Query-by-Example is to require the user to know very little in order to get started and to minimize the number of concepts that he subsequently has to learn in order to understand and use the whole language. The language syntax is simple, yet it covers a wide variety of complex transactions. This is achieved through the use of the same operations for retrieval, manipulation, definition, and control (to the extent possible). The language operations should mimic, as much as possible, manual table manipulation, thus capturing the simplicity, symmetry and neutrality of the relational The formulation of a transaction should capture the user's thought process, thereby providing freedom to formulate a transaction. The system should allow the user to create and drop tables dynamically from the data base; it must also provide the user with a dynamic capability for defining control statements and security features. The architecture of the Query-by-Example language addresses all the requirements just mentioned. The results of various psychological studies of the language7 show that it requires less than three hours of instruction for nonprogrammers to acquire the skill to make fairly complicated queries. Such queries would otherwise require the user to know first order predicate calculus. Other nonprocedural languages that deal with the same topic are
For example, the principle idea of JPDDs relates to the idea of Query-By-Example (QBE) REF as it is known from the database domain.
Query-by-Example : a data base language
IBM Syst. J.
IBM Syst. J.
Computer Science