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  2. Nested set model - Wikipedia

    en.wikipedia.org/wiki/Nested_set_model

    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".

  3. Array DBMS - Wikipedia

    en.wikipedia.org/wiki/Array_DBMS

    Transformation of a query to a more efficient, but equivalent version during array query optimization. Due to the massive sizes of arrays in scientific/technical applications in combination with often complex queries, optimization plays a central role in making array queries efficient. Both hardware and software parallelization can be applied.

  4. Data orientation - Wikipedia

    en.wikipedia.org/wiki/Data_orientation

    In particular, advanced query engines often leverage each orientation's advantages, and convert from one orientation to the other as part of their execution. As an example, an Apache Spark query may read data from Apache Parquet (column-oriented) load it into Spark internal in-memory format (row-oriented)

  5. Database model - Wikipedia

    en.wikipedia.org/wiki/Database_model

    The flat (or table) model consists of a single, two-dimensional array of data elements, where all members of a given column are assumed to be similar values, and all members of a row are assumed to be related to one another. For instance, columns for name and password that might be used as a part of a system security database.

  6. Relational algebra - Wikipedia

    en.wikipedia.org/wiki/Relational_algebra

    In 1998 Chris Date and Hugh Darwen proposed a language called Tutorial D intended for use in teaching relational database theory, and its query language also draws on ISBL's ideas. [9] Rel is an implementation of Tutorial D. Bmg is an implementation of relational algebra in Ruby which closely follows the principles of Tutorial D and The Third ...

  7. FDA Issues Urgent Warning on Dangers of Common Dog Medication

    www.aol.com/lifestyle/fda-issues-urgent-warning...

    The United States Food and Drugs Administration is warning pet owners about a common medication given to pets to treat arthritis. The F.D.A. now says that the drug Librela may be associated with ...

  8. What is ‘toasted skin syndrome'? Heating pads and blankets ...

    www.aol.com/toasted-skin-syndrome-heating-pads...

    Manhattan-based dermatologist Dr. Brendan Camp, M.D., said that toasted skin syndrome, officially known as erythema ab igne (EAI), is a "pattern of discoloration that occurs in areas of skin after ...

  9. SQL - Wikipedia

    en.wikipedia.org/wiki/SQL

    SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...