fix(planner): corretly handle catalog in statements

[andylokandy]

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Summary

• Parser: permit to specify catalog for DATABASE, TABLE and VIEW statements.
• Planner: lowercase all catalog, database, and tables names
• The other minor refactors.

Changelog

• Bug Fix
• Improvement

Related Issues

Part of #5907

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1 Ignored Deployment

Name	Status	Preview	Updated
databend	⬜️ Ignored (Inspect)		Jun 12, 2022 at 4:57AM (UTC)

[mergify]

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[BohuTANG]

workspace/tests/suites/0_stateless/05_ddl/05_0003_ddl_alter_database_v2.stdout 2022-06-12 00:30:24.425825160 +0000
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@@ -1,3 +1,5 @@
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+ERROR 1105 (HY000) at line 44: Code: 1003, displayText = Unknown database 'b'.
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+ERROR 1105 (HY000) at line 45: Code: 1003, displayText = Unknown database 'a'.
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system
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INFORMATION_SCHEMA
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a

[sundy-li]

lowercase all catalog, database, and tables names

Is this behavior commonly used in other DBMS ? I thought it's always case-sensitive.

[leiysky]

lowercase all catalog, database, and tables names

Is this behavior commonly used in other DBMS ? I thought it's always case-sensitive.

In most of the databases, the default behaviour is case-insensitive.

And the case-sensitivity of identifiers is controled in different ways, for example:

• SQL Server has variables SQL_IDENTIFIER_CASE and SQL_QUOTED_IDENTIFIER_CASE to control this document
• The rule of MySQL is complicated, but in most case, the identifiers are case-insensitive https://dev.mysql.com/doc/refman/8.0/en/identifier-case-sensitivity.html
• In Postgres, quoted identifiers are case-sensitive, and the rest are case-insensitive, which basically follows ANSI SQL
• Snowflake is compatible with Postgres, however, it still provide some variables to control the case-sensitivity as SQL Server does, to support different data upstream(we are going to follow this way). https://docs.snowflake.com/en/sql-reference/identifiers-syntax.html

This is work about normalizing the convention of identifiers, which is correlated with #5717 .

This PR only makes minor refactor of AST and unifies the behaviour of identifier case handling in new planner. It doesn't aim to resolve the issue of identifier case.

I have made an offline discussion with @andylokandy , we decide to get rest work done later.