Mercurial > hg > monetdb-java
diff example/SQLcopyinto.java @ 0:a5a898f6886c
Copy of MonetDB java directory changeset e6e32756ad31.
author | Sjoerd Mullender <sjoerd@acm.org> |
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date | Wed, 21 Sep 2016 09:34:48 +0200 (2016-09-21) |
parents | |
children | f1de7262d8d9 b9b35ca2eec2 |
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new file mode 100644 --- /dev/null +++ b/example/SQLcopyinto.java @@ -0,0 +1,111 @@ +/* + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + * + * Copyright 1997 - July 2008 CWI, August 2008 - 2016 MonetDB B.V. + */ + +import java.sql.*; +import java.io.*; +import java.util.*; +import nl.cwi.monetdb.mcl.net.*; +import nl.cwi.monetdb.mcl.io.*; + +/** + * This example demonstrates how the MonetDB JDBC driver can facilitate + * in performing COPY INTO sequences. This is mainly meant to show how + * a quick load can be performed from Java. + * + * @author Fabian Groffen + */ + +public class SQLcopyinto { + public static void main(String[] args) throws Exception { + // make sure the driver is loaded + Class.forName("nl.cwi.monetdb.jdbc.MonetDriver"); + // request a connection suitable for Monet from the driver manager + // note that the database specifier is currently not implemented, for + // Monet itself can't access multiple databases. + // turn on debugging + Connection con = DriverManager.getConnection("jdbc:monetdb://localhost/database", "monetdb", "monetdb"); + + // get a statement to execute on + Statement stmt = con.createStatement(); + + String query = "CREATE TABLE example (id int, val varchar(24))"; + try { + stmt.execute(query); + } catch (SQLException e) { + System.out.println(query + ": " + e.getMessage()); + System.exit(1); + } + + // now create a connection manually to perform a load, this can + // of course also be done simultaneously with the JDBC + // connection being kept connected + + MapiSocket server = new MapiSocket(); + + server.setDatabase("database"); + server.setLanguage("sql"); + + try { + List warning = + server.connect("localhost", 50000, "monetdb", "monetdb"); + if (warning != null) { + for (Iterator it = warning.iterator(); it.hasNext(); ) { + System.out.println(it.next().toString()); + } + } + + BufferedMCLReader in = server.getReader(); + BufferedMCLWriter out = server.getWriter(); + + String error = in.waitForPrompt(); + if (error != null) + throw new Exception(error); + + query = "COPY INTO example FROM STDIN USING DELIMITERS ',','\\n';"; + // the leading 's' is essential, since it is a protocol + // marker that should not be omitted, likewise the + // trailing semicolon + out.write('s'); + out.write(query); + out.newLine(); + for (int i = 0; i < 100; i++) { + out.write("" + i + ",val_" + i); + out.newLine(); + } + out.writeLine(""); // need this one for synchronisation over flush() + error = in.waitForPrompt(); + if (error != null) + throw new Exception(error); + // disconnect from server + server.close(); + } catch (IOException e) { + System.err.println("unable to connect: " + e.getMessage()); + System.exit(-1); + } catch (Exception e) { + System.err.println(e.getMessage()); + System.exit(-1); + } + + query = "SELECT COUNT(*) FROM example"; + ResultSet rs = null; + try { + rs = stmt.executeQuery(query); + } catch (SQLException e) { + System.out.println(query + ": " + e.getMessage()); + System.exit(1); + } + if (rs != null && rs.next()) + System.out.println(rs.getString(1)); + + // free resources, close the statement + stmt.close(); + // close the connection with the database + con.close(); + + } +}