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Design Patterns - Coggle Diagram
Design Patterns
EAV Model
object-attribute-value
open schema
entity represents data item being described
attribute represents data that describes an entity
value is the value of that attribute
Tree
a special case of graphs
connected graph without cycles
node is the root of a subtree
has one less edge
than it has nodes
Hierarchies
directed tree
subordination and inheritance
inheritance
have roles filled by entities
Tencer Meta-Model
each entity is an object
each object is unique
object has properties - attributes of an
entity
object may be a repository
Nested Sets
the single-table representation of
hierarchies
a tree with left and right nested
sets with number pairs
Data Manipulation
adding and editing
recalculating of the ID
removing
recalculating of borders and ID
selection
the purpose of this model
Graph
edges
undirected or directed
join two (and only two) nodes
nodes
Adjacency List
single-table representation of
hierarchies
Data Manipulation
adding and updating
easy
removal
all childrens of
a deleted node should be removed
selection
not a lot of possibilities of simple selection
Materialized Path
stores the path from the root to each node as a
string at that node
Data manipulation
adding and editing
recalculate ID of all children
removal
selection
the strength of this pattern