To modify existing records, use UPDATE statements.

Update Syntax

The UPDATE statement takes as input a comma-separated list of columns and new column values as name-value pairs in the SET clause, as shown in the following example:

UPDATE <table_name> SET <select_statement> | {<column_reference> = <expression> [ , ... ]} WHERE { Id = <expression>  } [ { AND | OR } ... ] 

<expression> ::=
  | @ <parameter> 
  | ?
  | <literal>

You can use the executeUpdate method of the Statement or PreparedStatement classes to execute data manipulation commands and retrieve the rows affected, as shown in the following example:

String cmd = "UPDATE Contacts SET Email='John' WHERE Id = ?";
PreparedStatement pstmt = connection.prepareStatement(cmd);
pstmt.setString(1, "6");
int count = pstmt.executeUpdate();
System.out.println(count + " rows were affected");
connection.close();