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Posted to codereview@trafodion.apache.org by liuyu000 <gi...@git.apache.org> on 2016/12/26 06:31:10 UTC
[GitHub] incubator-trafodion pull request #895: [TRAFODION-2412]update sql reference ...
GitHub user liuyu000 opened a pull request:
https://github.com/apache/incubator-trafodion/pull/895
[TRAFODION-2412]update sql reference manual about SEQUENCE and IDENTITY column
Changes proposed in this pull request:
\u2022 Add "CREATE SEQUENCE Statement", "DROP SEQUENCE Statement" & "ALTER SEQUENCE Statement".
\u2022 Add "Identity Columns".
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/liuyu000/incubator-trafodion sequence_identity
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/incubator-trafodion/pull/895.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #895
----
commit 967b2234dcc19ebdac8e906922e74b4651b2026f
Author: liu.yu <yu...@esgyn.cn>
Date: 2016-12-26T05:16:38Z
identity
commit 49b8a2724d583d9a606c4c9364dabb43fef8d72b
Author: liu.yu <yu...@esgyn.cn>
Date: 2016-12-26T06:25:46Z
create,alter,drop sequence
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[GitHub] incubator-trafodion pull request #895: [TRAFODION-2412]update sql reference ...
Posted by traflm <gi...@git.apache.org>.
Github user traflm commented on a diff in the pull request:
https://github.com/apache/incubator-trafodion/pull/895#discussion_r93874161
--- Diff: docs/sql_reference/src/asciidoc/_chapters/sql_language_elements.adoc ---
@@ -137,6 +137,74 @@ You can define specific default settings for columns when the table is created.
default settings for columns within tables. The default setting for a column is the value inserted in a row when an INSERT
statement omits a value for a particular column.
+<<<
+[[identity_columns]]
+== Identity Columns
+
+Trafodion introduces the ability defining an identity clause against a table column defined using a numeric type. The syntax is shown below.
+
+```
+GENERATED
+[ALWAYS | BY DEFAULT]
+AS IDENTITY [(identity_options)]
+```
+
+Ignoring the identity_options, which match those of the <<create_sequence_statement,CREATE_SEQUENCE_Statement>>, this syntax allows us to use three variations on the identity functionality.
+
+[[syntax_description_of_identity_columns]]
+=== Syntax Description of Identity Columns
+* `ALWAYS`
++
+Using ALWAYS forces the use of the identity. If an insert statement references the identity column, even to specify a NULL value, an error is produced.
+
+* `BY DEFAULT`
++
+Using BY DEFAULT allows you to use the identity if the column isn't referenced in the insert statement, but if the column is referenced, the specified value will be used in place of the identity. Attempting to specify the value NULL in this case results in an error, since identity columns are always NOT NULL.
--- End diff --
line is too long, need to limit each line's length, to generate a better HTML displaying.
This is a general comment, please consider to change all 'long lines' below into fixed width line.
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[GitHub] incubator-trafodion pull request #895: [TRAFODION-2412]update sql reference ...
Posted by liuyu000 <gi...@git.apache.org>.
Github user liuyu000 closed the pull request at:
https://github.com/apache/incubator-trafodion/pull/895
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