No, it is definitely not true of most databases. E.g., in PostgreSQL, you'll receive this error: ``` postgres=# CREATE TABLE foo ( some_text text NOT NULL ); CREATE TABLE postgres=# INSERT INTO foo VALUES (E'\xff' || 'test'); ERROR: invalid byte sequence for encoding "UTF8": 0xff postgres=# INSERT INTO foo VALUES (E'\x61' || 'test'); INSERT 0 1 postgres=# select * from foo; some_text ----------- atest (1 row) ``` MariaDB, which I'm using for MySQL here, but I believe MySQL proper behaves similarly, ``` MariaDB [(none)]> CREATE DATABASE mydatabase CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci; Query OK, 1 row affected (0.001 sec) MariaDB [(none)]> USE mydatabase; Database changed MariaDB [mydatabase]> CREATE TABLE foo ( some_txt text NOT NULL ); Query OK, 0 rows affected (0.125 sec) MariaDB [mydatabase]> INSERT INTO foo VALUES (X'ff'); ERROR 1366 (22007): Incorrect string value: '\xFF' for column `mydatabase`.`foo`.`some_txt` at row 1 MariaDB [mydatabase]> INSERT INTO foo VALUES (X'31'); Query OK, 1 row affected (0.098 sec) MariaDB [mydatabase]> select * from foo; +----------+ | some_txt | +----------+ | 1 | +----------+ 1 row in set (0.000 sec) ``` Now, MySQL has some legacy baggage; last I checked, the default encoding is still `latin1`, and in that encoding, any byte sequence is a valid string. (There are no malformed sequences of bytes, which isn't true in UTF-8.) Your exact example, in MariaDB: ``` MariaDB [mydatabase]> CREATE TABLE IF NOT EXISTS test_table ( -> some_text text NOT NULL -> ); Query OK, 0 rows affected (0.032 sec) MariaDB [mydatabase]> INSERT INTO test_table VALUES (CONCAT(0xff, 'bork')); ERROR 1366 (22007): Incorrect string value: '\xFFbork' for column `mydatabase`.`test_table`.`some_text` at row 1 ``` But again, the database here is configured to be UTF-8. Being configurable to a different encoding is different from the observed SQLite behavior, too: MySQL/MariaDB will encoding/decode appropriately, but it's still something it is very much aware of, in order to do so. (It's important for certain operations, like string comparison.)