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  2. Nested set model - Wikipedia

    en.wikipedia.org/wiki/Nested_set_model

    The nested set model is a solution to that problem. An alternative solution is the expression of the hierarchy as a parent-child relation. Joe Celko called this the adjacency list model. If the hierarchy can have arbitrary depth, the adjacency list model does not allow the expression of operations such as comparing the contents of hierarchies ...

  3. Database model - Wikipedia

    en.wikipedia.org/wiki/Database_model

    Database model for MediaWiki 1.28.0 (2017) Different types of database models A database model is a type of data model that determines the logical structure of a database.It fundamentally determines in which manner data can be stored, organized and manipulated.

  4. Database normalization - Wikipedia

    en.wikipedia.org/wiki/Database_normalization

    A basic objective of the first normal form defined by Codd in 1970 was to permit data to be queried and manipulated using a "universal data sub-language" grounded in first-order logic. [1] An example of such a language is SQL, though it is one that Codd regarded as seriously flawed. [2]

  5. Third normal form - Wikipedia

    en.wikipedia.org/wiki/Third_normal_form

    Third normal form (3NF) is a database schema design approach for relational databases which uses normalizing principles to reduce the duplication of data, avoid data anomalies, ensure referential integrity, and simplify data management.

  6. MySQL - Wikipedia

    en.wikipedia.org/wiki/MySQL

    MySQL (/ ˌ m aɪ ˌ ɛ s ˌ k juː ˈ ɛ l /) [6] is an open-source relational database management system (RDBMS). [6] [7] Its name is a combination of "My", the name of co-founder Michael Widenius's daughter My, [1] and "SQL", the acronym for Structured Query Language.

  7. First normal form - Wikipedia

    en.wikipedia.org/wiki/First_normal_form

    First normal form (1NF) is a property of a relation in a relational database. A relation is in first normal form if and only if no attribute domain has relations as elements. [1] Or more informally, that no table column can have tables as values.

  8. Explainer-What is the two-state solution to the Israel ...

    www.aol.com/news/explainer-two-state-solution...

    The two-state solution was the bedrock of the U.S.-backed peace process ushered in by the 1993 Oslo Accords, signed by Yasser Arafat of the Palestine Liberation Organization (PLO) and Israeli ...

  9. Set operations (SQL) - Wikipedia

    en.wikipedia.org/wiki/Set_operations_(SQL)

    The following example EXCEPT query returns all rows from the Orders table where Quantity is between 1 and 49, and those with a Quantity between 76 and 100. Worded another way; the query returns all rows where the Quantity is between 1 and 100, apart from rows where the quantity is between 50 and 75.