Extensions
Usage
The tables in the PostgreSQL database can be read as if they were normal DuckDB tables, but the underlying data is read directly from PostgreSQL at query time.  
```sql
SHOW ALL TABLES;
```  
<div class="narrow_table monospace_table"></div>  
| name  |
| ----- |
| uuids |  
```sql
SELECT * FROM uuids;
```  
<div class="narrow_table monospace_table"></div>  
| u                                    |
| ------------------------------------ |
| 6d3d2541-710b-4bde-b3af-4711738636bf |
| NULL                                 |
| 00000000-0000-0000-0000-000000000001 |
| ffffffff-ffff-ffff-ffff-ffffffffffff |  
It might be desirable to create a copy of the PostgreSQL databases in DuckDB to prevent the system from re-reading the tables from PostgreSQL continuously, particularly for large tables.  
Data can be copied over from PostgreSQL to DuckDB using standard SQL, for example:  
```sql
CREATE TABLE duckdb_table AS FROM postgres_db.postgres_tbl;
```