Update README.md

Mytherin · web-flow · commit 325132e3cbfa · 2024-03-04T13:39:09.000+01:00
diff --git a/README.md b/README.md
@@ -8,7 +8,6 @@ To make a Postgres database accessible to DuckDB use the `ATTACH` command:
 
 ```sql
 ATTACH 'dbname=postgresscanner' AS postgres_db (TYPE postgres);
-USE postgres_db;
 ```
 
 The `ATTACH` command takes as input a [`libpq` connection string](https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNSTRING) - which is a set of `key=value` pairs separated by spaces. Below are some example connection strings and commonly used parameters. A full list of available parameters can be found [in the Postgres documentation](https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-PARAMKEYWORDS).
@@ -32,14 +31,14 @@ host=localhost port=5432 dbname=mydb connect_timeout=10
 The tables in the file can be read as if they were normal DuckDB tables, but the underlying data is read directly from Postgres at query time.
 
 ```sql
-D SHOW TABLES;
+D SHOW ALL TABLES;
 ┌───────────────────────────────────────┐
 │                 name                  │
 │                varchar                │
 ├───────────────────────────────────────┤
 │ uuids                                 │
 └───────────────────────────────────────┘
-D SELECT * FROM uuids;
+D SELECT * FROM postgres_db.uuids;
 ┌──────────────────────────────────────┐
 │                  u                   │
 │                 uuid                 │
@@ -51,170 +50,7 @@ D SELECT * FROM uuids;
 └──────────────────────────────────────┘
 ```
 
-It might be desirable to create a copy of the Postgres databases in DuckDB to prevent the system from re-reading the tables from Postgres continuously, particularly for large tables.
-
-Data can be copied over from Postgres to DuckDB using standard SQL, for example:
-
-```sql
-CREATE TABLE duckdb_table AS FROM postgres_db.postgres_tbl;
-```
-
-## Writing Data to Postgres
-
-In addition to reading data from Postgres, the extension allows you to create tables, ingest data into Postgres and make other modifications to a Postgres database using standard SQL queries.
-
-This allows you to use DuckDB to, for example, export data that is stored in a Postgres database to Parquet, or read data from a Parquet file into Postgres.
-
-Below is a brief example of how to create a new table in Postgres and load data into it.
-
-```sql
-ATTACH 'dbname=postgresscanner' AS postgres_db (TYPE postgres);
-CREATE TABLE postgres_db.tbl(id INTEGER, name VARCHAR);
-INSERT INTO postgres_db.tbl VALUES (42, 'DuckDB');
-```
-Many operations on Postgres tables are supported. All these operations directly modify the Postgres database, and the result of subsequent operations can then be read using Postgres.
-Note that if modifications are not desired, `ATTACH` can be run with the `READ_ONLY` property which prevents making modifications to the underlying database. For example:
-
-```sql
-ATTACH 'dbname=postgresscanner' AS postgres_db (TYPE postgres, READ_ONLY);
-```
-
-Below is a list of supported operations.
-
-###### CREATE TABLE
-```sql
-CREATE TABLE postgres_db.tbl(id INTEGER, name VARCHAR);
-```
-
-###### INSERT INTO
-```sql
-INSERT INTO postgres_db.tbl VALUES (42, 'DuckDB');
-```
-
-###### SELECT
-```sql
-SELECT * FROM postgres_db.tbl;
-┌───────┬─────────┐
-│  id   │  name   │
-│ int64 │ varchar │
-├───────┼─────────┤
-│    42 │ DuckDB  │
-└───────┴─────────┘
-```
-
-###### COPY
-```sql
-COPY postgres_db.tbl TO 'data.parquet';
-COPY postgres_db.tbl FROM 'data.parquet';
-```
-
-###### UPDATE
-```sql
-UPDATE postgres_db.tbl SET name='Woohoo' WHERE id=42;
-```
-
-###### DELETE
-```sql
-DELETE FROM postgres_db.tbl WHERE id=42;
-```
-
-###### ALTER TABLE
-```sql
-ALTER TABLE postgres_db.tbl ADD COLUMN k INTEGER;
-```
-
-###### DROP TABLE
-```sql
-DROP TABLE postgres_db.tbl;
-```
-
-###### CREATE VIEW
-```sql
-CREATE VIEW postgres_db.v1 AS SELECT 42;
-```
-
-###### CREATE SCHEMA/DROP SCHEMA
-```sql
-CREATE SCHEMA postgres_db.s1;
-CREATE TABLE postgres_db.s1.integers(i int);
-INSERT INTO postgres_db.s1.integers VALUES (42);
-SELECT * FROM postgres_db.s1.integers;
-┌───────┐
-│   i   │
-│ int32 │
-├───────┤
-│    42 │
-└───────┘
-DROP SCHEMA postgres_db.s1;
-```
-
-###### Transactions
-```sql
-CREATE TABLE postgres_db.tmp(i INTEGER);
-BEGIN;
-INSERT INTO postgres_db.tmp VALUES (42);
-SELECT * FROM postgres_db.tmp;
-┌───────┐
-│   i   │
-│ int64 │
-├───────┤
-│    42 │
-└───────┘
-ROLLBACK;
-SELECT * FROM postgres_db.tmp;
-┌────────┐
-│   i    │
-│ int64  │
-├────────┤
-│ 0 rows │
-└────────┘
-```
-
-## Running SQL Queries in Postgres with postgres_query
-
-The postgres_query function allows you to run arbitrary SQL within an attached database. `postgres_query` takes the name of the attached Postgres database to execute the query in, as well as the SQL query to execute. The result of the query is returned.
-
-```sql
-postgres_query(attached_database::VARCHAR, query::VARCHAR)
-```
-
-###### Example
-
-```sql
-ATTACH 'dbname=postgresscanner' AS s (TYPE POSTGRES);
-SELECT * FROM postgres_query('s', 'SELECT * FROM cars LIMIT 3');
-┌──────────────┬───────────┬─────────┐
-│    brand     │   model   │  color  │
-│   varchar    │  varchar  │ varchar │
-├──────────────┼───────────┼─────────┤
-│ ferari       │ testarosa │ red     │
-│ aston martin │ db2       │ blue    │
-│ bentley      │ mulsanne  │ gray    │
-└──────────────┴───────────┴─────────┘
-```
-
-## Settings
-
-The extension exposes the following configuration parameters.
-
-|              name               |                                description                                 | default |
-|---------------------------------|----------------------------------------------------------------------------|---------|
-| pg_debug_show_queries           | DEBUG SETTING: print all queries sent to Postgres to stdout                | false   |
-| pg_experimental_filter_pushdown | Whether or not to use filter pushdown (currently experimental)             | false   |
-| pg_array_as_varchar             | Read Postgres arrays as varchar - enables reading mixed dimensional arrays | false   |
-| pg_connection_cache             | Whether or not to use the connection cache                                 | true    |
-| pg_connection_limit             | The maximum amount of concurrent Postgres connections                      | 64      |
-| pg_pages_per_task               | The amount of pages per task                                               | 1000    |
-| pg_use_binary_copy              | Whether or not to use BINARY copy to read data                             | true    |
-
-
-## Schema Cache
-
-To avoid having to continuously fetch schema data from Postgres, DuckDB keeps schema information - such as the names of tables, their columns, etc -  cached. If changes are made to the schema through a different connection to the Postgres instance, such as new columns being added to a table, the cached schema information might be outdated. In this case, the function `pg_clear_cache` can be executed to clear the internal caches.
-
-```sql
-CALL pg_clear_cache();
-```
+For more information on how to use the connector, refer to the [Postgres documentation on the website](https://duckdb.org/docs/extensions/postgres).
 
 ## Building & Loading the Extension
 
