Determining the Default Database

Problem

Has any database been selected as the default database? What is its name?

Solution

Use the DATABASE() function.

Discussion

SELECTDATABASE() returns the name of the default database or NULL if no database has been selected. The following Ruby code uses the statement to present a status display containing information about the current connection:

db = dbh.select_one("SELECT DATABASE()")[0]
puts "Default database: " + (db.nil? ? "(no database selected)" : db)

Note that before MySQL 4.1.1, DATABASE() returns an empty string (not NULL) if there is no current database.

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