question: private int encryptColumnContents ( String columnName , String tableName ) throws Exception { int recordsEncrypted = 0 ; String idColumnName = tableName + "_ID" ; StringBuffer selectSql = new StringBuffer ( ) ; selectSql . append ( "SELECT " + idColumnName + "," + columnName ) ; selectSql . append ( " FROM " + tableName ) ; selectSql . append ( " ORDER BY " + idColumnName ) ; StringBuffer updateSql = new StringBuffer ( ) ; updateSql . append ( "UPDATE " + tableName ) ; updateSql . append ( " SET " + columnName + "=?" ) ; updateSql . append ( " WHERE " + idColumnName + "=?" ) ; PreparedStatement selectStmt = null ; PreparedStatement updateStmt = null ; selectStmt = m_conn . prepareStatement ( selectSql . toString ( ) , ResultSet . TYPE_FORWARD_ONLY , ResultSet . CONCUR_UPDATABLE ) ; updateStmt = m_conn . prepareStatement ( updateSql . toString ( ) ) ; ResultSet rs = selectStmt . executeQuery ( ) ; for ( recordsEncrypted = 0 ; rs . next ( ) ; ++ recordsEncrypted ) { int id = rs . getInt ( 1 ) ; String value = rs . getString ( 2 ) ; value = SecureEngine . encrypt ( value ) ; updateStmt . setString ( 1 , value ) ; updateStmt . setInt ( 2 , id ) ; if ( updateStmt . executeUpdate ( ) != 1 ) { log . warning ( "EncryptError: Table=" + tableName + ", ID=" + id ) ; throw new Exception ( ) ; } } rs . close ( ) ; selectStmt . close ( ) ; updateStmt . close ( ) ; return recordsEncrypted ; }
target:  Encrypt all the contents of a database column.