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  2. Change data capture - Wikipedia

    en.wikipedia.org/wiki/Change_data_capture

    The most common forms of SCD are type 1 (overwrite), type 2 (maintain history) or 3 (only previous and current value). SCD 2 can be useful if history is needed in the target system. CDC overwrites in the target system (akin to SCD1), and is ideal when only the changed data needs to arrive at the target, i.e. a delta-driven dataset .

  3. Database trigger - Wikipedia

    en.wikipedia.org/wiki/Database_trigger

    [6] Before trigger is for checking data and deciding if operation should be permitted. If exception is thrown from before trigger then operation is aborted and no data are changed. In DB2 before triggers are read only — you can't modify data in before triggers. After triggers are designed for post processing after requested change was performed.

  4. Log trigger - Wikipedia

    en.wikipedia.org/wiki/Log_trigger

    Source: [1] A trigger cannot be attached to more than one operation (INSERT, DELETE, UPDATE), so a trigger must be created for each operation. The old and new values are exposed as fields of a record data structures. The names of these records can be defined, in this example they are named as O for old values and N for new values.

  5. Delete (SQL) - Wikipedia

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

    DELETE requires a shared table lock; Triggers fire; DELETE can be used in the case of: database link; DELETE returns the number of records deleted; Transaction log - DELETE needs to read records, check constraints, update block, update indexes, and generate redo / undo. All of this takes time, hence it takes time much longer than with TRUNCATE

  6. Template:Querylink - Wikipedia

    en.wikipedia.org/wiki/Template:Querylink

    This template creates an internal link to the specified page (1) with the specified query string (qs) of the form qs=name=value&name2=value2 and optionally the specified caption (2) which defaults to the specified page (1). The intended purpose of this template is to provide the ability to create internal links with a query string component ...

  7. Data clarification form - Wikipedia

    en.wikipedia.org/wiki/Data_clarification_form

    A data clarification form (DCF) [1] or data query form is a questionnaire specifically used in clinical research. The DCF is the primary data clarification tool from the trial sponsor or contract research organization (CRO) towards the investigator to clarify discrepancies and ask the investigator for clarification. The DCF is part of the data ...

  8. Database normalization - Wikipedia

    en.wikipedia.org/wiki/Database_normalization

    Codd went on to define the second normal form (2NF) and third normal form (3NF) in 1971, [5] and Codd and Raymond F. Boyce defined the Boyce–Codd normal form (BCNF) in 1974. [6] Ronald Fagin introduced the fourth normal form (4NF) in 1977 and the fifth normal form (5NF) in 1979. Christopher J. Date introduced the sixth normal form (6NF) in 2003.

  9. List of HTTP status codes - Wikipedia

    en.wikipedia.org/wiki/List_of_HTTP_status_codes

    Therefore, HTTP/1.1 added status codes 303 and 307 to distinguish between the two behaviours. [1]: §15.4 303 See Other (since HTTP/1.1) The response to the request can be found under another URI using the GET method. When received in response to a POST (or PUT/DELETE), the client should presume that the server has received the data and should ...