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  2. Rollback (data management) - Wikipedia

    en.wikipedia.org/wiki/Rollback_(data_management)

    SQL refers to Structured Query Language, a kind of language used to access, update and manipulate database. In SQL, ROLLBACK is a command that causes all data changes since the last START TRANSACTION or BEGIN to be discarded by the relational database management systems (RDBMS), so that the state of the data is "rolled back" to the way it was before those changes were made.

  3. Delete (SQL) - Wikipedia

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

    Does not free the space occupied by the data in the table (in the TABLESPACE) Does not reset the SEQUENCE value assigned to the table; DELETE works much slower than TRUNCATE; You can undo the operation of removing records by using the ROLLBACK command; DELETE requires a shared table lock; Triggers fire; DELETE can be used in the case of ...

  4. Update (SQL) - Wikipedia

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

    If it does, then only one of the join rows will be used to update the target row, but which one will be used is not readily predictable. [2] Because of this indeterminacy, referencing other tables only within sub-selects is safer, though often harder to read and slower than using a join. MySQL does not conform to ANSI standard. [3]

  5. List of SQL reserved words - Wikipedia

    en.wikipedia.org/wiki/List_of_SQL_reserved_words

    Reserved words in SQL and related products In SQL:2023 [3] In IBM Db2 13 [4] In Mimer SQL 11.0 [5] In MySQL 8.0 [6] In Oracle Database 23c [7] In PostgreSQL 16 [1] In Microsoft SQL Server 2022 [2]

  6. MyISAM - Wikipedia

    en.wikipedia.org/wiki/MyISAM

    Each MyISAM table is stored on disk in three files (if it is not partitioned). The files have names that begin with the table name and have an extension to indicate the file type. MySQL uses a .frm file to store the definition of the table, but this file is not a part of the MyISAM engine; instead it is a part of the server.

  7. Cascading failure - Wikipedia

    en.wikipedia.org/wiki/Cascading_failure

    In this context, the cascading failure is known by the term cascade failure. A cascade failure can affect large groups of people and systems. The cause of a cascade failure is usually the overloading of a single, crucial router or node, which causes the node to go down, even briefly. It can also be caused by taking a node down for maintenance ...

  8. Kessler syndrome - Wikipedia

    en.wikipedia.org/wiki/Kessler_syndrome

    The list could not easily account for objects under 20 cm (8 in) in size—in particular, debris from exploding rocket stages and several 1960s anti-satellite tests. [4] Returned spacecraft were microscopically examined for small impacts, and sections of Skylab and the Apollo Command/Service Module which were recovered were found to be pitted ...

  9. Cascade (computer virus) - Wikipedia

    en.wikipedia.org/wiki/Cascade_(computer_virus)

    The Cascade virus (also known as Herbstlaub, "autumn leaves" in Germany) is a prominent computer virus that was a resident written in assembly language, that was ...