- constraint key
- 约束键
English-Chinese computer dictionary (英汉计算机词汇大词典). 2013.
constraint key
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Constraint-induced movement therapy — (CI or CIMT) is a form of rehabilitation therapy that improves upper extremity function in stroke and other Central Nervous System damage victims by increasing the use of their affected upper limb.[1] The focus of CIMT is to combine restraint of… … Wikipedia
Key distribution in wireless sensor networks — Key distribution is an important issue in WSN design. It is a newly developing field due to the recent improvements in wireless communications.Wireless sensor networks are networks of small, battery powered, memory constraint devices named sensor … Wikipedia
Constraint — Mit Constraints (deutsch „Zwangsbedingungen“) werden in diversen Programmiersprachen Bedingungen definiert, die zwingend vom Wert einer Variablen erfüllt werden müssen, damit der Wert ins System übernommen werden kann. In Datenbanksystemen finden … Deutsch Wikipedia
The Berlin key — (also known as Schließzwangschlüssel (German) or close constraint key (English)) is a type of key lock. It was designed to force people to close and lock their doors (usually a front door or gate). Its particularity comes from the fact that it… … 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
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
Domain/key normal form — (DKNF) is a normal form used in database normalization which requires that the database contains no constraints other than domain constraints and key constraints. A domain constraint specifies the permissible values for a given attribute, while a … Wikipedia
Object Constraint Language — The Object Constraint Language (OCL) is a declarative language for describing rules that apply to Unified Modeling Language (UML) models developed at IBM and now part of the UML standard. Initially, OCL was only a formal specification language… … 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
Candidate key — In the relational model, a candidate key of a relvar (relation variable) is a set of attributes of that relvar such that # at all times it holds in the relation assigned to that variable that there are no two distinct tuples with the same values… … Wikipedia
Natural key — In relational model database design, a natural key is a candidate key that has a logical relationship to the attributes within that row. A natural key is sometimes called a domain key. The main advantage of a natural key over a surrogate key,… … Wikipedia
