SQL unique varchar case sensitivity question

Question

I'm trying to populate a SQL table with a list of words. The table itself it pretty simple:

CREATE TABLE WORDS(   ID BIGINT AUTO_INCREMENT,    WORD VARCHAR(128) NOT NULL UNIQUE,    PRIMARY KEY(ID) ); 

The problem I'm running into is this: when I do the following inserts back to back

INSERT INTO WORDS(WORD) VALUES('Seth'); INSERT INTO WORDS(WORD) VALUES('seth'); 

The second insert fails with a constraint violation ("Duplicate entry 'seth' for key 'WORD'").

How can I get the UNIQUE constraint on WORD to be case sensitive?

Answer 1

Looks like mysql is case insensitive by default:

You probably need to create the column with a case sensitive collation (e.g. utf8_bin):

CREATE TABLE WORDS (     ID BIGINT AUTO_INCREMENT,      WORD VARCHAR(128) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL UNIQUE,      PRIMARY KEY(ID) ); 

Answer 2

By default MySQL ignores differences in case and trailing spaces on varchar.

If you need it to be case sensitive, you can alter the table to be varchar(...) binary.

Use show create table to better understand how MySQL converts this to full notation.

If you need to pay attention to trailing spaces as well as be case sensitive, use varbinary instead of varchar.