-
1 checksum
"A calculated value that is used to test data for the presence of errors that can occur when data is transmitted or when it is written to disk. The checksum is calculated for a given chunk of data by sequentially combining all the bytes of data with a series of arithmetic or logical operations. After the data is transmitted or stored, a new checksum is calculated in the same way using the (possibly faulty) transmitted or stored data. If the two checksums do not match, an error has occurred, and the data should be transmitted or stored again. Checksums cannot detect all errors, and they cannot be used to correct erroneous data." -
2 calculated column
A type of column that displays the results of mathematical or logical operations or expressions instead of stored data. -
3 view
"In relational database management systems, a logical table created through the specification of one or more relational operations on one or more tables. A view is equivalent to a divided relation in the relational model."
См. также в других словарях:
logical operations — logical operations, the nonarithmetical operations in a computer, such as comparing, selecting, making references, matching, and sorting … Useful english dictionary
Logical positivism — (also known as logical empiricism, scientific philosophy, and neo positivism) is a philosophy that combines empiricism the idea that observational evidence is indispensable for knowledge with a version of rationalism incorporating mathematical… … Wikipedia
Logical truth — is one of the most fundamental concepts in logic, and there are different theories on its nature. A logical truth is a statement which is true and remains true under all reinterpretations of its components other than its logical constants. It is… … Wikipedia
Logical connective — This article is about connectives in classical logic. For connectors in natural languages, see discourse connective. For connectives and operators in other logics, see logical constant. For other logical symbols, see table of logic symbols. In… … Wikipedia
Logical conjunction — ∧ redirects here. For exterior product, see exterior algebra. Venn diagram of … Wikipedia
Logical disjunction — Disjunction redirects here. For separation of chromosomes, see Meiosis. For disjunctions in distribution, see Disjunct distribution. Venn diagram of the logical disjunction of A and B … Wikipedia
Logical NOR — This article is about NOR in the logical sense. For the electronic gate, see NOR gate. For other uses, see Nor. Venn diagram of In boolean logic, logical nor or joint denial is a truth functional operator which produces a result that is the… … Wikipedia
Logical line of operation — A logical line of operation (LLO) is an American military concept related to counter insurgency doctrine. In the traditional sense, a line of operations is an imaginary line between the force s base of operations and the objective.Cite… … Wikipedia
Logical Volume Manager (Linux) — LVM is a logical volume manager for the Linux kernel: it manages disk drives and similar mass storage devices, in particular large ones. The term volume refers to a disk drive or part thereof. It was originally written in 1998 by Heinz… … Wikipedia
Logical equality — For the corresponding concept in combinational logic, see XNOR gate. XNOR Logic Gate Symbol Logical equality is a logical operator that corresponds to equality in Boolean algebra and to the logical biconditional in propositional calculus. It… … Wikipedia
Logical Disk Manager — The Logical Disk Manager (diskmgmt.msc) is an implementation of a logical volume manager for Microsoft Windows NT, developed by Microsoft and Veritas Software. It was introduced with the Windows 2000 operating system, and is supported in Windows… … Wikipedia