enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Log trigger - Wikipedia

    en.wikipedia.org/wiki/Log_trigger

    In relational databases, the log trigger or history trigger is a mechanism for automatic recording of information about changes inserting or/and updating or/and deleting rows in a database table. It is a particular technique for change data capturing , and in data warehousing for dealing with slowly changing dimensions .

  3. Database trigger - Wikipedia

    en.wikipedia.org/wiki/Database_trigger

    Now let's say we have a trigger that uses AFTER instead. The code within the trigger is executed after the INSERT happens to the table. An example use of this trigger is creating an audit history of who has made inserts into the database, keeping track of the changes made. When using these options you need to keep a few things in mind.

  4. Query by Example - Wikipedia

    en.wikipedia.org/wiki/Query_by_Example

    Query by Example (QBE) is a database query language for relational databases. It was devised by Moshé M. Zloof at IBM Research during the mid-1970s, in parallel to the development of SQL . [ 1 ] It is the first graphical query language, using visual tables where the user would enter commands, example elements and conditions.

  5. MySQL - Wikipedia

    en.wikipedia.org/wiki/MySQL

    MySQL (/ ˌ m aɪ ˌ ɛ s ˌ k juː ˈ ɛ l /) [5] is an open-source relational database management system (RDBMS). [5] [6] Its name is a combination of "My", the name of co-founder Michael Widenius's daughter My, [7] and "SQL", the acronym for Structured Query Language.

  6. Write-ahead logging - Wikipedia

    en.wikipedia.org/wiki/Write-ahead_logging

    The changes are first recorded in the log, which must be written to stable storage, before the changes are written to the database. [2] The main functionality of a write-ahead log can be summarized as: [3] Allow the page cache to buffer updates to disk-resident pages while ensuring durability semantics in the larger context of a database system.

  7. Query language - Wikipedia

    en.wikipedia.org/wiki/Query_language

    A query language, also known as data query language or database query language (DQL), is a computer language used to make queries in databases and information systems. In database systems, query languages rely on strict theory to retrieve information. [1] A well known example is the Structured Query Language (SQL).

  8. Algorithms for Recovery and Isolation Exploiting Semantics

    en.wikipedia.org/wiki/Algorithms_for_Recovery...

    We create log records of the form (Sequence Number, Transaction ID, Page ID, Redo, Undo, Previous Sequence Number). The Redo and Undo fields keep information about the changes this log record saves and how to undo them. The Previous Sequence Number is a reference to the previous log record that was created for this transaction.

  9. Database engine - Wikipedia

    en.wikipedia.org/wiki/Database_engine

    The many types of indexes share the common property that they reduce the need to examine every entry when running a query. In large databases, this can reduce query time/cost by orders of magnitude. The simplest form of index is a sorted list of values that can be searched using a binary search with an adjacent reference to the location of the ...