enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Hierarchical and recursive queries in SQL - Wikipedia

    en.wikipedia.org/wiki/Hierarchical_and_recursive...

    In standard SQL:1999 hierarchical queries are implemented by way of recursive common table expressions (CTEs). Unlike Oracle's earlier connect-by clause, recursive CTEs were designed with fixpoint semantics from the beginning. [1] Recursive CTEs from the standard were relatively close to the existing implementation in IBM DB2 version 2. [1]

  3. Trino (SQL query engine) - Wikipedia

    en.wikipedia.org/wiki/Trino_(SQL_query_engine)

    Trino is an open-source distributed SQL query engine designed to query large data sets distributed over one or more heterogeneous data sources. [1] Trino can query data lakes that contain a variety of file formats such as simple row-oriented CSV and JSON data files to more performant open column-oriented data file formats like ORC or Parquet [2] [3] residing on different storage systems like ...

  4. Cigarette smokers problem - Wikipedia

    en.wikipedia.org/wiki/Cigarette_smokers_problem

    Once the smoker has finished his cigarette, the agent places two new random items on the table. This process continues forever. Three semaphores are used to represent the items on the table; the agent increases the appropriate semaphore to signal that an item has been placed on the table, and smokers decrement the semaphore when removing items ...

  5. Conditional (computer programming) - Wikipedia

    en.wikipedia.org/wiki/Conditional_(computer...

    1 2 3 Case-expressions in Haskell and match-expressions in F# and Haskell allow both switch-case and pattern matching usage. ^ In a Ruby case construct, regular expression matching is among the conditional flow-control alternatives available. For an example, see this Stack Overflow question.

  6. Propensity score matching - Wikipedia

    en.wikipedia.org/wiki/Propensity_score_matching

    R: propensity score matching is available as part of the MatchIt, [7] [8] optmatch, [9] or other packages. SAS: The PSMatch procedure, and macro OneToManyMTCH match observations based on a propensity score. [10] Stata: several commands implement propensity score matching, [11] including the user-written psmatch2. [12]

  7. Confusion matrix - Wikipedia

    en.wikipedia.org/wiki/Confusion_matrix

    In predictive analytics, a table of confusion (sometimes also called a confusion matrix) is a table with two rows and two columns that reports the number of true positives, false negatives, false positives, and true negatives. This allows more detailed analysis than simply observing the proportion of correct classifications (accuracy).

  8. Decision table - Wikipedia

    en.wikipedia.org/wiki/Decision_table

    Decision tables are a concise visual representation for specifying which actions to perform depending on given conditions. Decision table is the term used for a Control table or State-transition table in the field of Business process modeling; they are usually formatted as the transpose of the way they are formatted in Software engineering.

  9. Symbol table - Wikipedia

    en.wikipedia.org/wiki/Symbol_table

    The symbol table must have some means of differentiating references to the different "p"s. A common data structure used to implement symbol tables is the hash table. The time for searching in hash tables is independent of the number of elements stored in the table, so it is efficient for a large number of elements.