WHERE Clause Support in Connectors (Subsetting)

[MaximumTrainer]

Gap

TableConfiguration stores a whereClause field (up to 4096 characters) and the frontend supports entering it, but:

• The DatabaseConnector.fetchData() method signature does not accept a whereClause parameter.
• None of the four connector implementations apply a WHERE clause.
• JobService.processTable() for SUBSET mode only passes rowLimit to fetchData() — whereClause is ignored.

Affected files:

• backend/src/main/kotlin/com/opendatamask/connector/DatabaseConnector.kt
• All connector implementations
• backend/src/main/kotlin/com/opendatamask/model/TableConfiguration.kt

Required Work

• Extend DatabaseConnector.fetchData() to accept an optional whereClause parameter (with proper SQL-injection prevention via parameterized queries).
• Implement WHERE clause support in PostgreSQLConnector and AzureSQLConnector.
• Implement equivalent filtering for MongoDBConnector and MongoDBCosmosConnector (translate WHERE to MongoDB query filters).
• Wire TableConfiguration.whereClause into the JobService processing pipeline.