feat(4-3): add pgai example

Author: rgomezcasas

04-what_db_to_choose/3-pgai/compose.yml

@@ -1,6 +1,6 @@
 services:
   postgres_pgvector:
-    image: pgvector/pgvector:0.7.4-pg16
+    image: timescale/timescaledb-ha:pg16
     restart: always
 
     environment:

04-what_db_to_choose/3-pgai/databases/0-enable-pgai.sql

@@ -0,0 +1 @@
+CREATE EXTENSION IF NOT EXISTS ai CASCADE;

04-what_db_to_choose/3-pgai/databases/0-enable-pgvector.sql

@@ -4,6 +4,5 @@ CREATE TABLE mooc.courses (
 	id CHAR(4) PRIMARY KEY NOT NULL,
 	name VARCHAR(255) NOT NULL,
 	summary TEXT,
-	categories jsonb NOT NULL,
-	embedding vector(768)
+	categories jsonb NOT NULL
 );

04-what_db_to_choose/3-pgai/databases/1-mooc.sql

@@ -0,0 +1,6 @@
+SELECT ai.create_vectorizer(
+			   mooc.courses::regclass,
+			   destination => <embedding_table_name>,
+			   embedding => ai.embedding_openai(<model_name>, <dimensions>),
+			   chunking => ai.chunking_recursive_character_text_splitter(<column_name>)
+	   );