Any command other than those documented in the ij command reference
are handed to the current connection to execute directly. The statement's
closing semicolon, used by ij to determine that it has ended, is
not passed to the underlying connection. Only one statement at a time is passed
to the connection. If the underlying connection itself accepts semicolon-separated
statements (which Derby does not), they can be passed to the connection
using ij's Execute command to pass in a command string containing
semicolon-separated commands.
ij uses the result of the JDBC execute request to determine
whether it should print a number-of-rows message or display a result set.
If a JDBC execute request causes an exception, it displays the SQLState, if any, and error message.
Setting the ij property ij.showErrorCode to true displays the SQLException's error code (see ij properties reference).
The number-of-rows message for inserts, updates, and deletes conforms to
the JDBC specification for any SQL statement that does not have a result set.
DDL (data definition language) commands typically report "0 rows inserted/updated/deleted"
when they successfully complete.
To display a result set, ij formats a banner based on the JDBC ResultSetMetaData information returned from getColumnLabel and getColumnWidth. Long columns
wrap the screen width, using multiple lines. An & character
denotes truncation (ij limits displayed width of a column to 128
characters by default; see MaximumDisplayWidth command).
ij displays rows as it fetches them. If the underlying DBMS
materializes rows only as they are requested, ij displays a partial result
followed by an error message if there is a error in fetching a row partway
through the result set.
ij verifies that a connection exists before issuing statements
against it and does not execute SQL when no connection has yet been made.
There is no support in ij for the JDBC feature multiple result
sets.
