Fix SHOW COLUMNS and SHOW INDEX to resolve qualified table names

[Copilot]

SHOW COLUMNS and SHOW INDEX commands fail when using qualified table names (e.g., database.table), returning empty arrays instead of metadata. Works with unqualified names using USE context.

Changes

src/78show.js

• Updated database resolution in ShowColumns.prototype.execute() and ShowIndex.prototype.execute() to check this.table.databaseid before falling back to this.databaseid or default databaseid
• Parser already supports qualified names via Table rule, but execution code only checked legacy FROM table FROM database syntax

test/test2200.js

• Added test coverage for qualified table name resolution across both commands
• Uses before() and after() hooks for setup and cleanup
• Follows repository conventions with testId variable naming

Example

-- Now works
SHOW COLUMNS FROM mydb.users;
SHOW INDEX FROM mydb.users;

-- Cross-database queries
USE otherdb;
SHOW COLUMNS FROM mydb.users;  -- Returns correct columns

[!WARNING]

Original prompt

---

This section details on the original issue you should resolve

<filter_complete></filter_complete>

<issue_title>SHOW COLUMNS and SHOW INDEX don't resolve qualified table names.</issue_title>
<issue_description> SHOW COLUMNS and SHOW INDEX don't resolve qualified table names.

in test613.js i tried to use qualitfied table names, but it returns empty array [] instead of column/index metadata.

Works with unqualified names + USE context, fails with qualified names.

Root cause: Metadata commands don't parse qualified names correctly.
Needs parser/executor updates similar to how SELECT handles qualified names.

</issue_description>

<agent_instructions>Start by making a test2200.js test file that demonstrates the behavour.

Then change the src files to make it work. I expect that you will have to edit the grammar/parser. Please aims for small precise changes to the alasqlparser.jison file and after do yarn jison && yarn test to confirm.

Always run yarn format-all before making a commit. </agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes SHOW COLUMNS and SHOW INDEX don't resolve qualified table names. #2200

Original prompt

---

This section details on the original issue you should resolve

<issue_title>SHOW COLUMNS and SHOW INDEX don't resolve qualified table names.</issue_title>
<issue_description> SHOW COLUMNS and SHOW INDEX don't resolve qualified table names.

in test613.js i tried to use qualitfied table names, but it returns empty array [] instead of column/index metadata.

Works with unqualified names + USE context, fails with qualified names.

Root cause: Metadata commands don't parse qualified names correctly.
Needs parser/executor updates similar to how SELECT handles qualified names.

</issue_description>

<agent_instructions>Start by making a test2200.js test file that demonstrates the behavour.

Then change the src files to make it work. I expect that you will have to edit the grammar/parser. Please aims for small precise changes to the alasqlparser.jison file and after do yarn jison && yarn test to confirm.

Always run yarn format-all before making a commit. </agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes SHOW COLUMNS and SHOW INDEX don't resolve qualified table names. #2200

---

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[mathiasrw]

@copilot Please see the comments.

[Copilot]

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

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