JDBC Client (CLI client)

The JdbcClient program provides a command-line interface (inspired by mclient) for interactive SQL query processing. It is written entirely in Java using the JDBC API and the MonetDB JDBC driver. The program is available as a single small jar file jdbcclient.jre8.jar downloadable from MonetDB Java Download Area. The JAR file already includes the MonetDB JDBC driver, which is used to communicate with a MonetDB server, so no additional JAR files (or classpath settings) are needed.

The JdbcClient program supports startup options. To view them, type in a shell the command:

java -jar jdbcclient.jre8.jar --help

This command will show the following usage information:

Usage java -jar jdbcclient.jre8.jar
		[-h host[:port]] [-p port] [-f file] [-u user]
		[-l language] [-d database] [-e] [-D [table]]
		[--csvdir /path/to/csvfiles]] [-X<opt>]
		| [--help] | [--version]
or using long option equivalents --host --port --file --user --language
--dump --echo --database.
Arguments may be written directly after the option like -p50000.

If no host and port are given, localhost and 50000 are assumed.
An .monetdb file may exist in the user's home directory.  This file can contain
preferences to use each time JdbcClient is started.  Options given on the
command line override the preferences file.  The .monetdb file syntax is
<option>=<value> where option is one of the options host, port, file, mode
debug, or password.  Note that the last one is perilous and therefore not
available as command line option.
If no input file is given using the -f flag, an interactive session is
started on the terminal.

-h --host     The hostname of the host that runs the MonetDB database.  A port
              number can be supplied by use of a colon, i.e. -h somehost:12345.
-p --port     The port number to connect to.
-f --file     A file name to use either for reading or writing.  The file will
              be used for writing when dump mode is used (-D --dump).  In read
              mode, the file can also be an URL pointing to a plain text file
              that is optionally gzip compressed.
-u --user     The username to use when connecting to the database.
-d --database Try to connect to the given database (only makes sense if
              connecting to monetdbd).
-l --language Use the given language, defaults to 'sql'.
--csvdir      The directory path where csv data files are read or written when
              using ON CLIENT clause of COPY command.
--help        This help screen.
--version     Display driver version and exit.
-e --echo     Also outputs the contents of the input file, if any.
-q --quiet    Suppress printing the welcome header.
-D --dump     Dumps the given table(s), or the complete database if none given.
-Xoutput      The output mode when dumping.  Default is sql, xml may be used for
              an experimental XML output.
-Xhash        Use the given hash algorithm during challenge response. Supported
              algorithm names: SHA512, SHA384, SHA256 and SHA1.
-Xdebug       Writes a transmission log to disk for debugging purposes. If a
              file name is given, it is used, otherwise a file called
              monet<timestamp>.log is created.  A given file never be
              overwritten; instead a unique variation of the file is used.
-Xbatching    Indicates that a batch should be used instead of direct
              communication with the server for each statement.  If a number is
              given, it is used as batch size.  i.e. 8000 would execute the
              contents on the batch after each 8000 statements read.  Batching
              can greatly speedup the process of restoring a database dump.

Using the JdbcClient program

It is easy to start a JdbcClient program (assuming you have a MonetDB/SQL server running) from a shell, for example:

% java -jar jdbcclient.jre8.jar -p50000 -ddemo -umonetdb

Welcome to the MonetDB interactive JDBC terminal!
JDBC Driver: MonetDB Native Driver v3.2 (Liberica 20220127 based on MCL v1.21)
Database Server: MonetDB v11.43.9
Current Schema: sys
Type \q to quit (you can also use: quit or exit), \? or \h for a list of available commands
auto commit mode: on

As the password cannot be provided as a startup option, you will be asked to enter it after the password: prompt.

If you do not want to enter the password each time, use a .monetdb file, which contains the user and password settings.

If the authentication or connection fails, observe the printed error messages from JdbcClient (or the merovingian logs) for clues.

After a successful connection, the sql> prompt is shown, allowing you to enter any SQL query or backslash command and execute it using the enter-key. You can use multiple lines to enter the SQL query. To execute it, enter the ; character after the SQL query and press the enter-key. For example:

sql> select * from table_types
more> order by 2;
| table_type_id | table_type_name        |
|            20 | GLOBAL TEMPORARY TABLE |
|            30 | LOCAL TEMPORARY TABLE  |
|             3 | MERGE TABLE            |
|             5 | REMOTE TABLE           |
|             6 | REPLICA TABLE          |
|            10 | SYSTEM TABLE           |
|            11 | SYSTEM VIEW            |
|             0 | TABLE                  |
|             1 | VIEW                   |
9 rows
Elapsed Time: 2 ms

To view a list of available backslash commands, enter \? after the sql> prompt and press the enter-key.

sql> \?
Available commands:
\q       quits this program (you can also use: quit or exit)
\d       list available user tables and views in current schema
\dt      list available user tables in current schema
\dv      list available user views in current schema
\df      list available user functions in current schema
\dp      list available user procedures in current schema
\ds      list available user sequences in current schema
\dn      list available user schemas
\dS      list available system tables and views in sys/tmp schema
\dSt     list available system tables in sys/tmp schema
\dSv     list available system views in sys/logging schema
\dSf     list available system functions in current schema
\dSp     list available system procedures in current schema
\dSn     list available system schemas
\d <obj> describes the given table or view
\l<uri>  executes the contents of the given file or URL
\i<uri>  batch executes the inserts from the given file or URL
\vsci    validate sql system catalog integrity
\vsi <schema>  validate integrity of data in the given schema
\vdbi    validate integrity of data in all user schemas in the database
\? or \h this help screen

Use \q to quit the program. Alternatively, you can use quit or exit commands.

The following \v commands allow you to quickly validate the data integrity of: system catalogue tables, tables in one schema, or all user schemas in the database:

\vsi schema_name

The data integrity validations include:

  • Primary Key uniqueness
  • Primary Key column(s) NOT NULL constraint (currently only for \vsci)
  • Unique constraint uniqueness
  • Foreign Key referential integrity
  • Column NOT NULL constraint
  • Maximum string length constraint for columns of type char(n), varchar(n), clob(n), blob(n), json(n) and url(n)

It is advised to run \vsci command before and after an upgrade of the MonetDB server to check if the system catalogue tables are consistent.

Use \vsi my_schema to validate data for all tables of a specific schema.

Use \vdbi to validate the integrity of user data in all user schemas in the database.

The data integrity validation can take a long time to complete, depending on the number of user schemas, tables, columns and rows in the tables in a database.

The integrity validation functionality is still beta, so you may get false violations reported. If you encounter any, first check if you are using the latest available JdbcClient program. If so, report the issue via github.com/MonetDB/monetdb-java/issues.

The JdbcClient program does not support the SQL DEBUG <query>; command. Use the mclient program for those instead.

The JdbcClient program is provided as a test tool for performing connectivity and interactive tests using the integrated MonetDB JDBC driver. It is NOT recommended for production environments; the mclient program should be used instead.