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The nested set model is a technique for representing nested set collections (also known as trees or hierarchies) in relational databases.. It is based on Nested Intervals, that "are immune to hierarchy reorganization problem, and allow answering ancestor path hierarchical queries algorithmically — without accessing the stored hierarchy relation".
In computer science, a tree is a widely used abstract data type that represents a hierarchical tree structure with a set of connected nodes. Each node in the tree can be connected to many children (depending on the type of tree), but must be connected to exactly one parent, [ 1 ] [ 2 ] except for the root node, which has no parent (i.e., the ...
A hierarchical database model is a data model in which the data is organized into a tree-like structure. The data are stored as records which is a collection of one or more fields . Each field contains a single value, and the collection of fields in a record defines its type .
Relational database management systems such as IBM Db2, [11] Informix, [11] Microsoft SQL Server, [11] Oracle 8, [11] Sybase ASE, [11] and SQLite [14] support this type of tree for table indices, though each such system implements the basic B+ tree structure with variations and extensions.
In computer science, a B-tree is a self-balancing tree data structure that maintains sorted data and allows searches, sequential access, insertions, and deletions in logarithmic time. The B-tree generalizes the binary search tree , allowing for nodes with more than two children. [ 2 ]
In computer science, the log-structured merge-tree (also known as LSM tree, or LSMT [1]) is a data structure with performance characteristics that make it attractive for providing indexed access to files with high insert volume, such as transactional log data. LSM trees, like other search trees, maintain key-value pairs. LSM trees maintain data ...
A more involved example is the Boom hierarchy of the binary tree, list, bag and set abstract data types. [10] All these data types can be declared by three operations: null , which constructs the empty container, single , which constructs a container from a single element and append , which combines two containers of the same type.
The tree resolution and overall size is bounded by the pixel and image sizes. A region quadtree may also be used as a variable resolution representation of a data field. For example, the temperatures in an area may be stored as a quadtree, with each leaf node storing the average temperature over the subregion it represents.