Don't rename the databases directories directly. Instead, dump the database out, create a new database name (which, in turn, will create the new directory name) and then dump the database back into the new database name:

mysqldump -u username -p  olddatabase > olddbdump.sql
mysqladmin -u username -p create newdatabase
mysql -u username -p newdatabase < olddbdump.sql

Once you verified that the database is functional, you can drop the datase:

mysqladmin -u username -p drop oldatabase.

See here for reference.

In your case, you probably want to create a tmp database, dump the db_1 database into that temp database, drop and recreate the db_2 database, then dump the db_2 database into the newly empty db_1 database.

Don't rename the databases directories directly. Instead, dump the database out, create a new database name (which, in turn, will create the new directory name) and then dump the database back into the new database name:

mysqldump -u username -p  olddatabase > olddbdump.sql
mysqladmin -u username -p create newdatabase
mysql -u username -p newdatabase < olddbdump.sql

Once you verified that the database is functional, you can drop the datase:

mysqladmin -u username -p drop oldatabase.

See here for reference.

In your case, you probably want to create a tmp database, dump the db_1 database into that temp database, drop and recreate the db_2 database, then dump the db_2 database into the newly empty db_1 database.

Don't rename the databases directories directly. Instead, dump the database out, create a new database name (which, in turn, will create the new directory name) and then dump the database back into the new database name:

mysqldump -u username -p -v olddatabase > olddbdump.sql
mysqladmin -u username -p create newdatabase
mysql -u username -p newdatabase < olddbdump.sql

Once you verified that the database is functional, you can drop the datase:

mysqladmin -u username -p drop oldatabase.

See here for reference.

In your case, you probably want to create a tmp database, dump the db_1 database into that temp database, drop and recreate the db_2 database, then dump the db_2 database into the newly empty db_1 database.

Don't rename the databases directories directly. Instead, dump the database out, create a new database name (which, in turn, will create the new directory name) and then dump the database back into the new database name:

mysqldump -u username -p  olddatabase > olddbdump.sql
mysqladmin -u username -p create newdatabase
mysql -u username -p newdatabase < olddbdump.sql

Once you verified that the database is functional, you can drop the datase:

mysqladmin -u username -p drop oldatabase.

See here for reference.

In your case, you probably want to create a tmp database, dump the db_1 database into that temp database, drop and recreate the db_2 database, then dump the db_2 database into the newly empty db_1 database.