Databases Reference
In-Depth Information
Table options
Other attributes that influence the table's behavior may be specified using the
Table
options
dialog:
The options are:
•
PACK_KEYS
: Setting this attribute results in a smaller index. This can be read
faster but takes more time to update. Available for the
MyISAM
storage engine.
•
CHECKSUM
: This makes MySQL compute a checksum for each row. This
results in slower updates, but finding of corrupted tables becomes easier.
Available for
MyISAM
only.
•
DELAY_KEY_WRITE
: This instructs MySQL not to write the index updates
immediately, but to queue them for writing later. This improves performance
but there is a negative trade-off—the index might need to be r
ebuilt in case
miscellaneous-optimization-tips.html
). Available for
MyISAM
only.
•
TRANSACTIONAL
,
PAGE_CHECKSUM
: Applies to the
Aria
storage engine,
previously known as
Maria
. The
TRANSACTIONAL
option marks this table
as being transactional; however, the exact meaning of this option varies as
future versions of this storage engine will gain more transactional features.
PAGE_CHECKSUM
computes a checksum on all index pages. Currently
documented at
http://kb.askmonty.org/en/aria-storage-engine
.
•
ROW_FORMAT
: To the storage engines that support this feature (
MyISAM
,
InnoDB
,
PBXT
, and
Aria
), a choice of row format is presented. The default
value being the current state of this table's row format.
•
AUTO_INCREMENT
: This changes the auto-increment value. It is shown
only if the table's primary key has the auto-increment attribute.
Emptying or deleting a table
Emptying a table (erasing its data) and deleting a table (erasing its data and the
table's structure) can be done with the
Empty
the
table
(TRUNCATE)
and
Delete
the
table
(DROP)
links located in the
Delete
data
or
table
section.
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