import sqlite3

conn = sqlite3.connect('socks5.db') # , isolation_level=None) # для включения autocommit
cur = conn.cursor()

cur.execute("""CREATE TABLE IF NOT EXISTS socks5(
    id INTEGER PRIMARY KEY, -- нужен ли тут AUTOINCREMENT? NOT NULL?
    host TEXT, -- NOT NULL?
    port INTEGER,
    CONSTRAINT host_port UNIQUE(host, port)
); -- WITHOUT ROWID?""")

cur.execute("INSERT INTO socks5 VALUES(NULL, ?, ?);", ("127.0.0.1", 9050))

try:
    cur.execute("INSERT INTO socks5 VALUES(NULL, ?, ?);", ("127.0.0.1", 9050))
except sqlite3.IntegrityError as e: # UNIQUE constraint failed: socks5.host, socks5.port
    print(e)

cur.execute("INSERT INTO socks5 VALUES(NULL, ?, ?);", ("127.0.0.1", 9051))

#     with conn:
#         cur.execute(...)
# Аналог:
#     cur.execute(...)
#     conn.commit()

cur.execute("SELECT * FROM socks5;")
print(cur.fetchall())
cur.execute("DELETE FROM socks5;")

CREATE TABLE IF NOT EXISTS socks(
    id INTEGER PRIMARY KEY AUTOINCREMENT, 
    host TEXT NOT NULL,
    port INTEGER NOT NULL,
    version INTEGER NOT NULL,
    CONSTRAINT host_port UNIQUE(host, port)
);
CREATE INDEX IF NOT EXISTS index_version ON socks(version);