How do you insert and update vector data in pgvector?

-- Insert a single row with a vector literal
INSERT INTO documents (content, embedding)
VALUES ('Hello world', '[0.1, 0.2, 0.3, ...]');

-- Insert multiple rows in one statement
INSERT INTO documents (id, content, embedding) VALUES
    (1, 'Python tutorial', '[0.11, 0.22, 0.33]'),
    (2, 'JavaScript guide', '[0.44, 0.55, 0.66]'),
    (3, 'Hiking tips', '[0.77, 0.88, 0.99]');

-- Insert from a Python list (psycopg2)
# import psycopg2
# embedding = [0.1, 0.2, 0.3]   # list of floats from embedding model
# cur.execute(
#     "INSERT INTO documents (content, embedding) VALUES (%s, %s)",
#     (text, embedding)   # psycopg2 converts list to vector literal
# )

-- Update an existing embedding:
UPDATE documents
SET embedding = '[0.11, 0.21, 0.31]'
WHERE id = 1;

-- Upsert (insert or update on conflict):
INSERT INTO documents (id, content, embedding)
VALUES (1, 'Updated Python tutorial', '[0.12, 0.23, 0.34]')
ON CONFLICT (id) DO UPDATE SET
    content   = EXCLUDED.content,
    embedding = EXCLUDED.embedding;

-- Cast a text literal to vector explicitly:
SELECT '[1,2,3]'::vector;   -- explicit cast notation
SELECT CAST('[1,2,3]' AS vector(3));