Skilirium

All stages of Data modeller

Stage 5

Derive the logical data model

Derives a normalised logical data model and traces anomalies to their causes

56 knobits (20 knowledge, 36 skills) · Produces: logical model · Builds on: Build the conceptual model and taxonomies

Knobit map

Each mark is one knobit. Knobits higher up build on the ones below them; select one to open it.

K-501 Recognises an insertion anomaly in a logical data model501K-502 Recognises an update anomaly in a logical data model502K-503 Recognises a deletion anomaly in a logical data model503K-504 Recognises a repeating group in an entity504K-505 Recognises an attribute holding several facts505K-506 Recognises an attribute with several meanings506K-507 Recognises attributes held as name-value rows507K-508 Recognises a partial dependency on a composite key508K-509 Recognises a transitive dependency between non-key attributes509K-510 Recognises a stored derivable attribute510K-511 Recognises a non-superkey determinant in a 3NF entity511K-512 Recognises independent multi-valued facts in one entity512K-513 Recognises a join dependency kept in one entity513K-514 Recognises a lossy decomposition514K-515 Recognises a functional dependency lost in a decomposition515K-516 Recognises attributes inapplicable to some instances516K-517 Recognises an unstable or meaningful primary key517K-518 Recognises an entity identified only by a system-assigned key518K-519 Recognises undeclared subtype constraints519K-520 Recognises independently changing histories in one entity520K-521 Recognises an unresolved many-to-many relationship521K-522 Recognises a polymorphic association522K-523 Recognises a connection trap523K-524 Recognises a fan trap524K-525 Recognises a chasm trap525K-526 Recognises a redundant relationship526K-527 Recognises overlapping entities527K-528 Recognises one entity split by value into several528K-529 Recognises a relationship contradicting its data rule529K-530 Recognises a constraint implied by neither keys nor domains530K-531 Traces a logical-model anomaly to its structural cause531K-532 Records the functional dependencies of an entity532K-533 Decomposes an entity along a functional dependency without loss533K-534 Resolves a many-to-many relationship into an associative entity534K-535 Replaces a repeating group with a dependent entity535K-536 Introduces subtypes for attributes applying to only some instances536K-551 Explains functional dependency551K-552 Explains candidate key and prime attribute552K-553 Explains the insertion, update and deletion anomalies553K-554 Explains first normal form554K-555 Explains second normal form555K-556 Explains third normal form556K-557 Explains Boyce-Codd normal form557K-558 Explains multivalued dependency and fourth normal form558K-559 Explains join dependency and fifth normal form559K-560 Explains sixth normal form for temporal data560K-561 Explains domain-key normal form561K-562 Explains attribute domains562K-563 Explains lossless-join decomposition563K-564 Explains dependency preservation564K-565 Explains derived data and point-in-time snapshots565K-566 Explains supertype and subtype constraints566K-567 Explains relationship cardinality and optionality567K-568 Explains natural keys, surrogate keys and key stability568K-569 Explains the connection, fan and chasm traps569K-570 Explains an entity type as the realisation of one business concept570
  • Circle: skill
  • Square: knowledge

Knobits of this stage

KnobitType
K-501Recognises an insertion anomaly in a logical data modelSkill
K-502Recognises an update anomaly in a logical data modelSkill
K-503Recognises a deletion anomaly in a logical data modelSkill
K-504Recognises a repeating group in an entitySkill
K-505Recognises an attribute holding several factsSkill
K-506Recognises an attribute with several meaningsSkill
K-507Recognises attributes held as name-value rowsSkill
K-508Recognises a partial dependency on a composite keySkill
K-509Recognises a transitive dependency between non-key attributesSkill
K-510Recognises a stored derivable attributeSkill
K-511Recognises a non-superkey determinant in a 3NF entitySkill
K-512Recognises independent multi-valued facts in one entitySkill
K-513Recognises a join dependency kept in one entitySkill
K-514Recognises a lossy decompositionSkill
K-515Recognises a functional dependency lost in a decompositionSkill
K-516Recognises attributes inapplicable to some instancesSkill
K-517Recognises an unstable or meaningful primary keySkill
K-518Recognises an entity identified only by a system-assigned keySkill
K-519Recognises undeclared subtype constraintsSkill
K-520Recognises independently changing histories in one entitySkill
K-521Recognises an unresolved many-to-many relationshipSkill
K-522Recognises a polymorphic associationSkill
K-523Recognises a connection trapSkill
K-524Recognises a fan trapSkill
K-525Recognises a chasm trapSkill
K-526Recognises a redundant relationshipSkill
K-527Recognises overlapping entitiesSkill
K-528Recognises one entity split by value into severalSkill
K-529Recognises a relationship contradicting its data ruleSkill
K-530Recognises a constraint implied by neither keys nor domainsSkill
K-531Traces a logical-model anomaly to its structural causeSkill
K-532Records the functional dependencies of an entitySkill
K-533Decomposes an entity along a functional dependency without lossSkill
K-534Resolves a many-to-many relationship into an associative entitySkill
K-535Replaces a repeating group with a dependent entitySkill
K-536Introduces subtypes for attributes applying to only some instancesSkill
K-551Explains functional dependencyKnowledge
K-552Explains candidate key and prime attributeKnowledge
K-553Explains the insertion, update and deletion anomaliesKnowledge
K-554Explains first normal formKnowledge
K-555Explains second normal formKnowledge
K-556Explains third normal formKnowledge
K-557Explains Boyce-Codd normal formKnowledge
K-558Explains multivalued dependency and fourth normal formKnowledge
K-559Explains join dependency and fifth normal formKnowledge
K-560Explains sixth normal form for temporal dataKnowledge
K-561Explains domain-key normal formKnowledge
K-562Explains attribute domainsKnowledge
K-563Explains lossless-join decompositionKnowledge
K-564Explains dependency preservationKnowledge
K-565Explains derived data and point-in-time snapshotsKnowledge
K-566Explains supertype and subtype constraintsKnowledge
K-567Explains relationship cardinality and optionalityKnowledge
K-568Explains natural keys, surrogate keys and key stabilityKnowledge
K-569Explains the connection, fan and chasm trapsKnowledge
K-570Explains an entity type as the realisation of one business conceptKnowledge