row constraint

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• Complexity of constraint satisfaction — The complexity of constraint satisfaction is the application of computational complexity theory on constraint satisfaction. It has mainly been studied for discriminating between tractable and intractable classes of constraint satisfaction… …   Wikipedia

• Check Constraint — A check constraint (also known as table check constraint) is a condition that defines valid data when adding or updating an entry in a table of a relational database. A check constraint is applied to each row in the table. The constraint must be… …   Wikipedia

• Propagation constraint — In database systems, a propagation constraint details what should happen to a related table when we update a row or rows of a target table (Paul Beynon Davies, 2004, p.108). Tables are linked using primary key to foreign key relationships. It is… …   Wikipedia

• Local consistency — In constraint satisfaction, local consistency conditions are properties of constraint satisfaction problems related to the consistency of subsets of variables or constraints. Several such conditions exist, the most known being node consistency,… …   Wikipedia

• Optimality theory — (frequently abbreviated OT) is a linguistic model proposing that the observed forms of language arise from the interaction between conflicting constraints. OT models grammars as systems that provide mappings from inputs to outputs; typically, the …   Wikipedia

• Foreign key — In the context of relational databases, a foreign key is a referential constraint between two tables. [ [http://www.visualcase.com/kbase/database basics foreign keys.htm For a simpler visualization, see VisualCase.com] ] The foreign key… …   Wikipedia

• Mathematics of Sudoku — The class of Sudoku puzzles consists of a partially completed row column grid of cells partitioned into N regions each of size N cells, to be filled in using a prescribed set of N distinct symbols (typically the numbers {1, ..., N}), so that each …   Wikipedia

• Null (SQL) — The Greek lowercase omega (ω) character is used to represent Null in database theory. Null is a special marker used in Structured Query Language (SQL) to indicate that a data value does not exist in the database. Introduced by the creator of the… …   Wikipedia

• 2-satisfiability — In computer science, 2 satisfiability (abbreviated as 2 SAT or just 2SAT) is the problem of determining whether a collection of two valued (Boolean or binary) variables with constraints on pairs of variables can be assigned values satisfying all… …   Wikipedia

• Sudoku — Not to be confused with Sodoku. A Sudoku puzzle …   Wikipedia

• Unique key — In relational database design, a unique key can uniquely identify each row in a table, and is closely related to the Superkey concept. A unique key comprises a single column or a set of columns. No two distinct rows in a table can have the same… …   Wikipedia