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How does InnoDB behave without a Primary Key? – Jeremy Cole
If the table has no PRIMARY KEY or suitable UNIQUE index, InnoDB internally generates a hidden clustered index on a synthetic column containing row ID values. The rows are ordered by the ID that InnoDB assigns to the rows in such a table. The row ID is a 6-byte field that increases monotonically as new rows are inserted. Thus, the rows ordered by the row ID are physically in insertion order.
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If the table has no PRIMARY KEY or suitable UNIQUE index, InnoDB internally generates a hidden clustered index on a synthetic column containing row ID values. The rows are ordered by the ID that InnoDB assigns to the rows in such a table. The row ID is a 6-byte field that increases monotonically as new rows are inserted. Thus, the rows ordered by the row ID are physically in insertion order.
http://ift.tt/16xd2d8
http://ift.tt/1qmsMs7
from Public RSS-Feed of Jeffery yuan. Created with the PIXELMECHANICS 'GPlusRSS-Webtool' at http://gplusrss.com http://ift.tt/1mKwqWY
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