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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
node is the root of the subtree
a special case of graphs
connected graph without cycles
has one less edge than it has nodes
Hierarchies
inheritance
directed tree
subordination and 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 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
selection
recalculating of borders and ID
removing
the purpose of this model
Graph
Edges
undirected or directed
join only two nodes
Nodes
Materialized path
stores the path from the root to each node as a string at htat node
Data manipulation
adding and editing
recalculate IDof all children
selecting
the strength of this pattern
removal
Adjacency List
single-table representstion of hierarchies
Data Manipulation
adding and editing
easy
removal
all childrens of a deleted node should be removed
selection
not a lot of possibilities of simple selection