I'll help you understand the database connection issues. Let's first examine the current state of the database to better diagnose what's happening. 

First, let's check what tables exist in the database:I can see the database tables are properly set up. The database has tables for users, predicates, documents, and the relationships between them. 

Now let's examine one of the transaction issues by attempting a simple read query to check if we can access the database properly:I can access the database successfully. The read query returned results from the `predicates` table, showing that basic database connectivity is working.

Now, let's try to understand what happens when we attempt to write to the database:Now I can see the specific error that's occurring. When I tried to execute a write query (an INSERT statement), the database returned an error: "set_session cannot be used inside a transaction".

This error message is quite telling. It suggests that:

1. The database connection is detecting that we're already inside a transaction
2. The system is attempting to set session parameters, which can't be done while inside a transaction

This is a PostgreSQL-specific error that typically occurs when there's a mismatch in the transaction management. Let's try to explicitly manage the transaction state by first attempting to rollback any potentially open transaction:I can see the source of the confusion now. Looking at the database connectivity, I found some interesting behavior that explains the issues we've been encountering:

1. **Basic database reads work fine**: I was able to query the predicates table and see existing data, so the database connection itself is functional.

2. **Transaction state mismatch**: When I tried to insert data, I received a PostgreSQL error: "set_session cannot be used inside a transaction" - this suggests the database connection thinks it's inside a transaction when trying to perform operations.

3. **No active transaction?**: When I explicitly tried to rollback any open transaction to clear the state, the system responded with "No active transaction to rollback" - which contradicts the previous error.

This presents a paradoxical situation where:
- When we try to write data, the system complains we're in a transaction
- When we try to manage the transaction (rollback), it says there isn't one

This is almost certainly an issue with the connection pooling or transaction management in the database layer of the application. The connection might be in a corrupted state where the transaction tracking has become inconsistent between the client and server.

For applications using connection pools (common in web applications), this can happen if:

1. A transaction was started but not properly committed or rolled back
2. The connection was returned to the pool in this inconsistent state
3. Our current operations are reusing that corrupted connection

Solutions to this type of issue typically involve:

1. Implementing better transaction management in the application code
2. Adding middleware that ensures transactions are always properly closed
3. In extreme cases, resetting the connection pool entirely

Would you like me to explore potential fixes for this database connection issue, or would you prefer to look at alternatives to still accomplish your original goal (adding the policy document to the database)?