Skilirium

6. etapp: Füüsilise andmemudeli kujundamine

Kompetentsi Andmete modelleerimine knobit · K-608 · Oskus

Recognises a hierarchy encoded redundantly

Mida see tähendab

A recursive relationship stored as a path string or nested-set numbers. The structure is held many times over, moving one node rewrites all its descendants, and no foreign key checks the encoding. A specific form of row 3.

Kuidas seda hinnatakse

Flags the deficient case and passes the acceptable one. Deficient: `branch.path = '/1/4/17/'` with no foreign key on the parts; moving branch 4 under another region rewrites every row below it, and a mistyped path loads Acceptable: `parent_branch_id` with a foreign key as the system of record; a path, nested set or closure table only as a derived structure with `derivation` and a DQ rule. A closure table has foreign keys on both columns

Vajalik

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