Inserting records into a MySQL table using Java

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北海茫月
北海茫月 2021-02-13 14:45

I created a database with one table in MySQL:

CREATE DATABASE iac_enrollment_system;

USE iac_enrollment_system;

CREATE TABLE course(
    course_code CHAR(7),
          


        
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4条回答
  • 2021-02-13 15:07

    no that cannot work(not with real data):

    String sql = "INSERT INTO course " +
            "VALUES (course_code, course_desc, course_chair)";
        stmt.executeUpdate(sql);
    

    change it to:

    String sql = "INSERT INTO course (course_code, course_desc, course_chair)" +
            "VALUES (?, ?, ?)";
    

    Create a PreparedStatment with that sql and insert the values with index:

    PreparedStatement preparedStatement = conn.prepareStatement(sql);
    preparedStatement.setString(1, "Test");
    preparedStatement.setString(2, "Test2");
    preparedStatement.setString(3, "Test3");
    preparedStatement.executeUpdate(); 
    
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  • 2021-02-13 15:12

    This should work for any table, instead of hard-coding the columns.

    //Source details
        String sourceUrl = "jdbc:oracle:thin:@//server:1521/db";
        String sourceUserName = "src";
        String sourcePassword = "***";
    
        // Destination details
        String destinationUserName = "dest";
        String destinationPassword = "***";
        String destinationUrl = "jdbc:mysql://server:3306/db";
    
        Connection srcConnection = getSourceConnection(sourceUrl, sourceUserName, sourcePassword);
        Connection destConnection = getDestinationConnection(destinationUrl, destinationUserName, destinationPassword);
    
        PreparedStatement sourceStatement = srcConnection.prepareStatement("SELECT *  FROM src_table ");
        ResultSet rs = sourceStatement.executeQuery();
        rs.setFetchSize(1000); // not needed
    
    
        ResultSetMetaData meta = rs.getMetaData();
    
    
    
        List<String> columns = new ArrayList<>();
        for (int i = 1; i <= meta.getColumnCount(); i++)
            columns.add(meta.getColumnName(i));
    
        try (PreparedStatement destStatement = destConnection.prepareStatement(
                "INSERT INTO dest_table ("
                        + columns.stream().collect(Collectors.joining(", "))
                        + ") VALUES ("
                        + columns.stream().map(c -> "?").collect(Collectors.joining(", "))
                        + ")"
                )
        )
        {
            int count = 0;
            while (rs.next()) {
                for (int i = 1; i <= meta.getColumnCount(); i++) {
                    destStatement.setObject(i, rs.getObject(i));
                }
                
                destStatement.addBatch();
                count++;
            }
            destStatement.executeBatch(); // you will see all the rows in dest once this statement is executed
            System.out.println("done " + count);
    
        }

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  • 2021-02-13 15:17

    this can also be done like this if you don't want to use prepared statements.

    String sql = "INSERT INTO course(course_code,course_desc,course_chair)"+"VALUES('"+course_code+"','"+course_desc+"','"+course_chair+"');"
    

    Why it didnt insert value is because you were not providing values, but you were providing names of variables that you have used.

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  • 2021-02-13 15:27

    There is a mistake in your insert statement chage it to below and try : String sql = "insert into table_name values ('" + Col1 +"','" + Col2 + "','" + Col3 + "')";

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