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Topic: database keys and indexing
topics >
computer science >
database >
b-trees
Topic:
database implementation
Topic:
database queries, joins, and relational algebra
Topic:
database schema
Topic:
entity-relationship database model
Topic:
external search and sort
Topic:
hash table and hash functions
Topic:
full-text indexing
Topic:
relational database
Topic:
sort algorithms
Subtopic: foreign key
Quote: a database uniquely identifies every object [»coddEF_1990] Quote: the primary key plus table name uniquely identifies every row of a relational database; integrity is not enforced by other models [»coddEF_1990] Quote: a primary key is one or more domains that uniquely identifies tuples of a relation [»coddEF6_1970] Quote: the same data value in a database could be a primary key or could be a secondary key specifying a set of records [»bachCW11_1973] Quote: data in relational database addressed by relation name, attribute name, and primary key [»coddEF2_1982] Quote: the relational model uses user-defined and user-controlled primary keys as unique and permanent identifiers Quote: an Agenda item acts like a unique key and a category corresponds to an indexed, non-key field QuoteRef: chenPP3_1976 ;;14 "Basically, an entity key is a group of attributes such that the mapping from the entity set to the corresponding group of value sets is one-to-one
Subtopic: hash joins
Quote: a foreign key refers to a row of another table via a value from the same domain as the primary key [»coddEF_1990] Quote: a foreign key consists of values for the primary key of a relation [»coddEF6_1970] Quote: foreign keys blur the distinction between entities and relations Quote: referential integrity if every foreign key refers to a primary key unless marked as a missing values [»coddEF_1990]
Subtopic: B-tree
Quote: criss-cross hash joins interleaves zoned partitions configured through page maps; low memory and I/O costs; even better if ordered [»gopaRD7_2001]
Subtopic: integrity constraint
Quote: B-trees widely used to implement relational database systems; primary commercial application [»bayeR_2002]
Subtopic: problems with keys
Quote: integrity constraints checked automatically, no voluntary action; concern of the community of users [»coddEF_1990]
Quote: soft keys can be null; merging soft keys propagates softness to all keys [»kentW1_1984] Quote: problems with user-controlled keys as permanent surrogates: can be changed, different keys for same entity, entities without keys Quote: with user-controlled keys, an equi-join on common key values may be different that a join on common entities
Topic: b-trees (16 items)
Topic: database implementation (18 items)
Topic: database queries, joins, and relational algebra (33 items)
Topic: database schema (29 items)
Topic: entity-relationship database model (21 items)
Topic: external search and sort (23 items)
Topic: hash table and hash functions (41 items)
Topic: full-text indexing (35 items)
Topic: relational database (34 items)
Topic: sort algorithms
(24 items)