360f7b3d33
This commit moves the Features page from the section for developers to the top level in the page tree. This involves: - Moving the source files to the *features* folder from the *using-scylla* folder. - Moving images into *features/images* folder. - Updating references to the moved resources. - Adding redirections to the moved pages. Closes scylladb/scylladb#20401
66 lines
1.6 KiB
ReStructuredText
66 lines
1.6 KiB
ReStructuredText
.. _row-deletions:
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Row deletions
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-------------
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Row deletions are operations where you delete an entire clustering row by using a ``DELETE`` statement, specifying the values of all clustering key columns, but **not** specifying any particular regular column.
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The following is an example of a row deletion with CDC enabled.
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#. Start with a basic table and insert some data into it.
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.. code-block:: cql
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CREATE TABLE ks.t (pk int, ck int, v int, PRIMARY KEY (pk, ck)) WITH cdc = {'enabled': 'true'};
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INSERT INTO ks.t (pk, ck, v) VALUES (0,0,0);
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#. Display the contents of the table
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.. code-block:: cql
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SELECT * from ks.t;
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returns:
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.. code-block:: none
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pk | ck | v
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----+----+---
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0 | 0 | 0
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(1 rows)
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#. Remove the row where the primary key 0 and the clustering key is 0.
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.. code-block:: cql
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DELETE FROM ks.t WHERE pk = 0 AND ck = 0;
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#. Check that after performing a row deletion, querying the deleted row returns 0 results:
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.. code-block:: cql
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SELECT * from ks.t WHERE pk = 0 AND ck = 0;
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returns:
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.. code-block:: none
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pk | ck | v
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----+----+------
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(0 rows)
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Note that row deletions *are different than column deletions*, which are ``DELETE`` statements with some particular non-key column specified, like the following:
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.. code-block:: cql
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DELETE v FROM ks.t WHERE pk = 0 AND ck = 0;
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Column deletions are equivalent to UPDATEs with the column set to null, e.g.:
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.. code-block:: cql
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UPDATE ks.t SET v = null WHERE pk = 0 AND ck = 0;
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You can read about UPDATEs in the :ref:`corresponding section <updates>`.
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