Is there an open-source SQL database that has the concept of Oracle's "rowid" pseudo-column? -


I know that MySQL and PostgreSQL [1] not is such a concept, so I am there There is a concept in which there is an open source SQL database interested in finding out.

[1] Later it was reported that PostgreSQL has a queue column in place.

PostgreSQL is the concept.

For a short list of pseudocolumns, see PostgreSQL , out of which ctid is interested in:

ctid (tuple identifier) ​​

The identifier that describes the physical location of the inside of the database, a couple of numbers are represented by ctid: block number, and that block Inside the Tupal index.

This is a direct analog of Oracle 's MyISQL .

As for MySQL , the physical location of one line is not available for the front end.

, rowid is a file offset from the beginning, and that the index is stored in the leaves.

In InnoDB , the table is Index Organized by design, that means they are always some kind of primary key, and a InnoDB The index above the table is used as the key one line indicator as that code.

This is also true for the oracle of the indexed tables, for which there is not a rowid in a data file A physical indicator in the block, but a logical ROWID , or UROWID

if you enter ROWID from a In Index Organized tabl e Oracle , you will see that it has a different format (like * BAEBwPICwQL + ). This is actually an encoded primary key value.

Note that if you have any column primary key , MySQL will create a hidden surrogate primary key on which You will never control.

That's why you always have any type of create primary key code> a INODB in the table: it's free, and you get control over the columns is.


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