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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: 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.
However, delete and update operations are more problematic: deletes must leave an empty space, or the rows' offsets would change; the same goes for updates, as the length of the rows becomes shorter; if the update makes the row longer, the row is fragmented. To defragment rows and claim empty space, the OPTIMIZE TABLE command must be executed.
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.
New features include a "fast migration" option to migrate the data from the command-line instead of the GUI, a SSL certificate generator, improved SQL auto-completion, a new table data import and export wizard, and MySQL Enterprise Firewall support. Version 6.3.8, MySQL Workbench for MacOS has incompatibilities with MacOS Sierra. [26]
MySQL Cluster is implemented through the NDB or NDBCLUSTER storage engine for MySQL ("NDB" stands for Network Database). MySQL Federated – allows a user to create a table that is a local representation of a foreign (remote) table. It utilizes the MySQL client library API as a data transport, treating the remote data source the same way other ...
There are graphical and command line utilities in Windows, Linux, and Mac OS X environments. Zen Control Center (CC) is the main utility that enables the user to create and manipulate databases and tables, to access servers and clients, to set configurations and properties, and to edit data. Through CC, the user can access a series of other ...
The command is available for various operating systems including DOS, Microware OS-9, [1] IBM OS/2, [2] Microsoft Windows [3] and ReactOS. [4] It is analogous to the Unix rm command and to the Stratus OpenVOS delete_file and delete_dircommands. [5] DEC RT-11, [6] OS/8, [7] RSX-11, [8] and OpenVMS [9] also provide the delete command which can be ...
Command Prompt, also known as cmd.exe or cmd, is the default command-line interpreter for the OS/2, [1] eComStation, ArcaOS, Microsoft Windows (Windows NT family and Windows CE family), and ReactOS [2] operating systems. On Windows CE .NET 4.2, [3] Windows CE 5.0 [4] and Windows Embedded CE 6.0 [5] it is referred to as the Command Processor ...