David Mollitor created HIVE-23149:
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Summary: Consistency of Parsing Object Identifiers
Key: HIVE-23149
URL: https://issues.apache.org/jira/browse/HIVE-23149
Project: Hive
Issue Type: Improvement
Reporter: David Mollitor
Assignee: David Mollitor
There needs to be better consistency with handling of object identifiers
(database, tables, column, view, function, etc.). I think it makes sense to
standardize on the same rules which MySQL/MariaDB uses for their column names
so that Hive can be more of a drop-in replacement for these.
The two important things to keep in mind are:
1// Permitted characters in quoted identifiers include the full Unicode Basic
Multilingual Plane (BMP), except U+0000
2// If any components of a multiple-part name require quoting, quote them
individually rather than quoting the name as a whole. For example, write
{{`my-table`.`my-column`}}, not {{`my-table.my-column`}}.
[https://dev.mysql.com/doc/refman/8.0/en/identifiers.html]
[https://dev.mysql.com/doc/refman/8.0/en/identifier-qualifiers.html]
That is to say:
{code:sql}
-- Select all rows from a table named `default.mytable`
-- (Yes, the table name itself has a period in it. This is valid)
SELECT * FROM `default.mytable`;
-- Select all rows from database `default`, table `mytable`
SELECT * FROM `default`.`mytable`;
{code}
This plays out in a couple of ways. There may be more, but these are the ones
I know about already:
1// Hive generates incorrect syntax: [HIVE-23128]
2// Hive throws exception if there is a period in the table name. This is an
invalid response. Table name may have a period in them. More likely than not,
it will throw 'table not found' exception since the user most likely
accidentally used backticks incorrectly and meant to specify a db and a table
separately. [HIVE-16907]
Once we have the parsing figured out and support for backticks to enclose UTF-8
strings, then the backend database needs to actually support the UTF-8
character set. It currently does not: [HIVE-1808]
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