[
https://issues.apache.org/jira/browse/HIVE-16575?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15997069#comment-15997069
]
Eugene Koifman commented on HIVE-16575:
---------------------------------------
One way to enforce not null constraint is to have the optimizer add
enforce_not_null UDF which throws if it sees a NULL.
So if 'b' has not null constraint,
Insert into T select a,b,c... would become
Insert into T select a, enforce_not_null(b), c.....
This would work for any table type.
> Support for 'UNIQUE' and 'NOT NULL' constraints
> -----------------------------------------------
>
> Key: HIVE-16575
> URL: https://issues.apache.org/jira/browse/HIVE-16575
> Project: Hive
> Issue Type: New Feature
> Components: CBO, Logical Optimizer, Parser
> Reporter: Jesus Camacho Rodriguez
> Assignee: Jesus Camacho Rodriguez
> Attachments: HIVE-16575.01.patch, HIVE-16575.patch
>
>
> Follow-up on HIVE-13076.
> This issue add support for SQL 'UNIQUE' and 'NOT NULL' constraints when we
> create a table / alter a table
> (https://www.postgresql.org/docs/9.6/static/sql-createtable.html).
> As with PK and FK constraints, currently we do not enforce them; thus, the
> constraints need to use the DISABLE option, but they will be stored and can
> be enabled for rewriting/optimization using RELY.
> This patch also adds support for inlining the constraints next to the column
> type definition, i.e., 'column constraints'.
> Some examples of the extension to the syntax included in the patch:
> {code:sql}
> CREATE TABLE table3 (x string NOT NULL DISABLE, PRIMARY KEY (x) DISABLE,
> CONSTRAINT fk1 FOREIGN KEY (x) REFERENCES table2(a) DISABLE);
> CREATE TABLE table4 (x string CONSTRAINT nn4_1 NOT NULL DISABLE, y string
> CONSTRAINT nn4_2 NOT NULL DISABLE, UNIQUE (x) DISABLE, CONSTRAINT fk2 FOREIGN
> KEY (x) REFERENCES table2(a) DISABLE,
> CONSTRAINT fk3 FOREIGN KEY (y) REFERENCES table2(a) DISABLE);
> CREATE TABLE table12 (a STRING CONSTRAINT nn12_1 NOT NULL DISABLE NORELY, b
> STRING);
> CREATE TABLE table13 (a STRING NOT NULL DISABLE RELY, b STRING);
> CREATE TABLE table14 (a STRING CONSTRAINT nn14_1 NOT NULL DISABLE RELY, b
> STRING);
> CREATE TABLE table15 (a STRING REFERENCES table4(x) DISABLE, b STRING);
> CREATE TABLE table16 (a STRING CONSTRAINT nn16_1 REFERENCES table4(x) DISABLE
> RELY, b STRING);
> ALTER TABLE table16 CHANGE a a STRING REFERENCES table4(x) DISABLE NOVALIDATE;
> ALTER TABLE table12 CHANGE COLUMN b b STRING CONSTRAINT nn12_2 NOT NULL
> DISABLE NOVALIDATE;
> ALTER TABLE table13 CHANGE b b STRING NOT NULL DISABLE NOVALIDATE;
> {code}
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
