Category: MySQL

To add a foreign key (grade_id) to an existing table (users), follow the following steps:

ALTER TABLE users ADD grade_id SMALLINT UNSIGNED NOT NULL DEFAULT 0;
ALTER TABLE users ADD CONSTRAINT fk_grade_id FOREIGN KEY (grade_id) REFERENCES grades(id);

Source

Prompt for password:

 mysql -u username -p databasename < filename.sql  

Enter password directly (not secure):

 mysql -u username -pPlainPassword databasename filename.sql 

Example:

mysql -u root -p wp_users < wp_users.sql

mysql -u root -pPassword123 wp_users --default-character-set=utf8 < wp_users.sql

See also:
4.5.1.5. Executing SQL Statements from a Text File

Error: 1017 Can’t find file! (errno: 2)

mysql> REPAIR TABLE database.postmeta USE_FRM;