Code in android (databases)

The slash is the Java character escape: it means that the following character is special, and should not have it's normal meaning. In this case \" says 'insert a double quote in the string instead of terminating the string'

"A\"B\"C"

Would give you a string containing

A"B"C

There are several "special" codes in Java:

\b   Backspace
\f   Form feed
\n   Newline
\t   Tab
\r   Carriage return
\"   Double quote
\\   Backslash

But please, do yourself a favour and don't do it like that! Never concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead.