Sqlite Note

1. return the rows being inserted, deleted, or updated.
   See RETURNING
   Example Usage:

   CREATE TABLE t0(
   a INTEGER PRIMARY KEY,
   b DATE DEFAULT CURRENT_TIMESTAMP,
   c INTEGER
   );
   INSERT INTO t0(c) VALUES (random()), (random()) RETURNING *;
   

2. use PRAGMA foreign_keys = ON; to enable foreign key check.

3. specific types like CHAR(30), CHAR(50) are eventually converted into sqlite built-in types like TEXT. So there is no length check for string.
   Datatypes In SQLite #3.1.1. Affinity Name Examples

4. Primary Key uauslly not the true primary key, and the rowid is.
   exception: Integer Primary Key becomes an alias for the rowid in Rowid Tables.
   If there is not integer primary key alias as rowid, then rowid is not persistent. To See rowid:

   select rowid, * from table; -- or `oid`, `_rowid_`
   

   See Rowid Tables