fix: scope ER diagram, dump and export to the selected database on multi-database connections

[debba]

What this fixes

When a single MySQL/MariaDB connection has several databases selected, a few features kept operating on the connection's primary database (the first one) instead of the database you actually picked:

• ER diagram — opening the diagram for database B showed database A's tables again ([Bug]: ER Diagram fails to regenerate when switching databases on the same MySQL/MariaDB connection #345).
• Dump — dumping a non-primary database failed with Table 'first_db.some_table' doesn't exist ([Bug]: Database Export/Dump Context Switching Failure in Multi-Database Environment #334).
• CSV/JSON export — exporting a result ran the query against the primary database for the same reason ([Bug]: Database Export/Dump Context Switching Failure in Multi-Database Environment #334).

The common cause is the same: the backend resolves the target database from the request, but the frontend never sent which database was selected, so every call fell back to database.primary().

Changes

ER diagram

• The selected database is now forwarded to get_schema_snapshot. The MySQL driver already treats the schema argument as the database name, so each database renders its own schema. This is centralized in a small resolveDiagramSchema helper (with unit tests) and leaves PostgreSQL untouched, since it always sends an explicit schema.
• Each diagram window now gets a unique label per connection/database/schema. Previously the window label was hard-coded, so a second diagram either collided with the first or reused its view. If a window for the same target is already open we just focus it.

Dump

• dump_database now receives the selected database and binds the pool to it, so unqualified statements (SHOW CREATE TABLE, SELECT * FROM ...) run against the right database.
• The dump dialog reloads the target database's tables when it opens, so the table list reflects that database instead of a stale or wrong-database list. The export button waits until the reload finishes.

Export

• export_query_to_file now receives the selected database. The frontend resolves it from the tab's schema and falls back to the active database, matching how execute_query already resolves it (so it works whether you export a table tab or a console result after switching databases).

The new backend parameters are all optional, so PostgreSQL and SQLite behavior is unchanged.

Testing

• cargo check passes.
• tsc --noEmit passes.
• Full frontend test suite passes (added cases for resolveDiagramSchema).
• Verified on a MySQL connection with multiple databases: ER diagram, dump and export now target the selected database.

Closes #345
Closes #334

[kilo-code-bot]

Code Review Summary

Status: 4 Issues Found | Recommendation: Address before merge

Overview

Severity	Count
CRITICAL	0
WARNING	3
SUGGESTION	1

Issue Details (click to expand)

WARNING

File	Line	Issue
src-tauri/src/dump_commands.rs	87	Header comment uses params.database (a DatabaseSelection enum) via its Display impl; for Multiple it only shows the first database. Consider using params.database.primary() explicitly for clarity.
src/components/modals/DumpDatabaseModal.tsx	55–59	refreshRef.current(databaseName) is called without error handling. If refreshDatabaseData rejects, this becomes an unhandled promise rejection.
src/components/modals/DumpDatabaseModal.tsx	136–137	databaseParam could send { database: undefined } when databaseName is falsy (e.g., empty string). The condition checks truthiness but the prop type is string which could be empty.

SUGGESTION

File	Line	Issue
src/components/modals/DumpDatabaseModal.tsx	220–223	Loading spinner has gap-2 class but only contains a single <Loader2 /> element with no accompanying text. Consider adding descriptive text or removing the unnecessary gap.

Files Reviewed (8 files)

• src-tauri/src/commands.rs — Window label uniqueness fix for ER diagrams. No issues.
• src-tauri/src/dump_commands.rs — 1 issue: params.database Display usage in header comment.
• src-tauri/src/export.rs — No issues. Clean optional parameter addition.
• src/components/modals/DumpDatabaseModal.tsx — 3 issues: unhandled promise rejection, potential undefined databaseParam, unnecessary gap class.
• src/pages/Editor.tsx — No issues. Clean database parameter resolution mirroring execute_query.
• src/pages/SchemaDiagramPage.tsx — No issues. Clean use of resolveDiagramSchema.
• src/utils/schemaDiagram.ts — No issues. Clean helper with good documentation.
• tests/utils/schemaDiagram.test.ts — No issues. Good test coverage for new helper.

Fix Link

Fix these issues in Kilo Cloud

[kilo-code-bot]

Code Review Summary

Status: 4 Issues Found | Recommendation: Address before merge

Overview

Severity	Count
CRITICAL	0
WARNING	3
SUGGESTION	1

Issue Details (click to expand)

WARNING

File	Line	Issue
src-tauri/src/dump_commands.rs	87	Header comment uses params.database (a DatabaseSelection enum) via its Display impl; for Multiple it only shows the first database. Consider using params.database.primary() explicitly for clarity.
src/components/modals/DumpDatabaseModal.tsx	55–59	refreshRef.current(databaseName) is called without error handling. If refreshDatabaseData rejects, this becomes an unhandled promise rejection.
src/components/modals/DumpDatabaseModal.tsx	136–137	databaseParam could send { database: undefined } when databaseName is falsy (e.g., empty string). The condition checks truthiness but the prop type is string which could be empty.

SUGGESTION

File	Line	Issue
src/components/modals/DumpDatabaseModal.tsx	220–223	Loading spinner has gap-2 class but only contains a single <Loader2 /> element with no accompanying text. Consider adding descriptive text or removing the unnecessary gap.

Files Reviewed (8 files)

• src-tauri/src/commands.rs — Window label uniqueness fix for ER diagrams. No issues.
• src-tauri/src/dump_commands.rs — 1 issue: params.database Display usage in header comment.
• src-tauri/src/export.rs — No issues. Clean optional parameter addition.
• src/components/modals/DumpDatabaseModal.tsx — 3 issues: unhandled promise rejection, potential undefined databaseParam, unnecessary gap class.
• src/pages/Editor.tsx — No issues. Clean database parameter resolution mirroring execute_query.
• src/pages/SchemaDiagramPage.tsx — No issues. Clean use of resolveDiagramSchema.
• src/utils/schemaDiagram.ts — No issues. Clean helper with good documentation.
• tests/utils/schemaDiagram.test.ts — No issues. Good test coverage for new helper.

Fix Link

Fix these issues in Kilo Cloud

---

_{Reviewed by kimi-k2.6-20260420 · Input: 132.9K · Output: 31K · Cached: 1.4M}