Examples of weka.core.converters.DatabaseLoader

weka.core.converters.DatabaseLoader
Reads Instances from a Database. Can read a database in batch or incremental mode.
In inremental mode MySQL and HSQLDB are supported.
For all other DBMS set a pseudoincremental mode is used:
In pseudo incremental mode the instances are read into main memory all at once and then incrementally provided to the user.
For incremental loading the rows in the database table have to be ordered uniquely.
The reason for this is that every time only a single row is fetched by extending the user query by a LIMIT clause.
If this extension is impossible instances will be loaded pseudoincrementally. To ensure that every row is fetched exaclty once, they have to ordered.
Therefore a (primary) key is necessary.This approach is chosen, instead of using JDBC driver facilities, because the latter one differ betweeen different drivers.
If you use the DatabaseSaver and save instances by generating automatically a primary key (its name is defined in DtabaseUtils), this primary key will be used for ordering but will not be part of the output. The user defined SQL query to extract the instances should not contain LIMIT and ORDER BY clauses (see -Q option).
In addition, for incremental loading, you can define in the DatabaseUtils file how many distinct values a nominal attribute is allowed to have. If this number is exceeded, the column will become a string attribute.
In batch mode no string attributes will be created.
Valid options are:
```
 -url <JDBC URL> The JDBC URL to connect to. (default: from DatabaseUtils.props file)
```
```
 -user <name> The user to connect with to the database. (default: none)
```
```
 -password <password> The password to connect with to the database. (default: none)
```
```
 -Q <query> SQL query of the form SELECT <list of columns>|* FROM <table> [WHERE] to execute. (default: Select * From Results0)
```
```
 -P <list of column names> List of column names uniquely defining a DB row (separated by ', '). Used for incremental loading. If not specified, the key will be determined automatically, if possible with the used JDBC driver. The auto ID column created by the DatabaseSaver won't be loaded.
```
```
 -I Sets incremental loading
```
@author Stefan Mutter (mutter@cs.waikato.ac.nz) @version $Revision: 7039 $ @see Loader

    }
    add(db,BorderLayout.SOUTH);
  }
  
  private boolean resetAndUpdateDatabaseLoaderIfChanged() {
    DatabaseLoader dbl = (DatabaseLoader)m_dsLoader.getLoader();
    String url = dbl.getUrl();
    String user = dbl.getUser();
    String password = dbl.getPassword();
    String query = dbl.getQuery();
    String keys = dbl.getKeys();
    
    boolean update = (!url.equals(m_dbaseURLText.getText()) || 
        !user.equals(m_userNameText.getText()) ||
        !password.equals(m_passwordText.getText()) ||
        !query.equalsIgnoreCase(m_queryText.getText())||
        !keys.equals(m_keyText.getText()));
    
    if (update) {
      dbl.resetStructure();  
      dbl.setUrl(m_dbaseURLText.getText());
      dbl.setUser(m_userNameText.getText());
      dbl.setPassword(new String(m_passwordText.getPassword()));
      dbl.setQuery(m_queryText.getText());
      dbl.setKeys(m_keyText.getText());
    }
    
    return update;
  }

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    buffer.append("Loder Class: " + loader.getLoader().getClass().getName()  + "\n");
    buffer.append("Global Info: " + loader.globalInfo()  + "\n");
    String className = loader.getLoader().getClass().getName();
    
    if(className.equalsIgnoreCase(DatabaseLoader.class.getName())) {
      DatabaseLoader databaseLoader = (DatabaseLoader)loader.getLoader();
            
      buffer.append("  Loader type: DatabaseLoader"  + "\n");
      buffer.append("Options: ");
      String[] options = databaseLoader.getOptions();    
      for(int i = 0; i < options.length; i++) {
        buffer.append(options[i] + "; ");
      }
      buffer.append("  URL: " + databaseLoader.getUrl() + "\n");
      buffer.append("  User: " + databaseLoader.getUser() + "\n");    
      buffer.append("  Password: " + "?" + "\n");  
      buffer.append("  Query: " + databaseLoader.getQuery() + "\n");
      buffer.append("  Key columns' name: " + databaseLoader.getKeys() + "\n");        
    }
    else if(className.equalsIgnoreCase(ArffLoader.class.getName())) {
      ArffLoader arffLoader = (ArffLoader)loader.getLoader();
      buffer.append("  Loader type: ArffLoader" + "\n");
    }

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    for(int i = 0; i < loaders.size(); i++) {
      Loader loader = (Loader)loaders.get(i);            
      String className = loader.getLoader().getClass().getName();
      
      if(className.equalsIgnoreCase(DatabaseLoader.class.getName())) {
        DatabaseLoader databaseLoader = (DatabaseLoader)loader.getLoader();
        if(env.getOutConnection() != null) {
          databaseLoader.setSource(env.getInConnection());
        }
      } else if(className.equalsIgnoreCase(ArffLoader.class.getName())) {
        ArffLoader arffLoader = (ArffLoader)loader.getLoader();
        // setup operation goes here
      } else if(className.equalsIgnoreCase(CSVLoader.class.getName())) {

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    if (query == null) {
      query = "";
    }
    
    try {
      DatabaseLoader dbl = new DatabaseLoader();
      dbl.setUser(user);
      dbl.setPassword(password);
      dbl.setUrl(uRL);
      dbl.setQuery(query);
      
      BeanContextSupport bc = new BeanContextSupport();
      bc.setDesignTime(true);
      
      Loader loaderComp = new Loader();

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    }
    add(holderP, BorderLayout.SOUTH);
  }
  
  private boolean resetAndUpdateDatabaseLoaderIfChanged() {
    DatabaseLoader dbl = (DatabaseLoader)m_dsLoader.getLoader();
    String url = dbl.getUrl();
    String user = dbl.getUser();
    String password = dbl.getPassword();
    String query = dbl.getQuery();
    String keys = dbl.getKeys();
    File propsFile = dbl.getCustomPropsFile();
    
    boolean update = (!url.equals(m_dbaseURLText.getText()) || 
        !user.equals(m_userNameText.getText()) ||
        !password.equals(m_passwordText.getText()) ||
        !query.equalsIgnoreCase(m_queryText.getText())||
        !keys.equals(m_keyText.getText()));
    
    if (propsFile != null && m_dbProps.getText().length() > 0) {
       update = (update || !propsFile.toString().equals(m_dbProps.getText()));        
    } else {
      update = (update || m_dbProps.getText().length() > 0);
    }
    
    if (update) {
      dbl.resetStructure();  
      dbl.setUrl(m_dbaseURLText.getText());
      dbl.setUser(m_userNameText.getText());
      dbl.setPassword(new String(m_passwordText.getPassword()));
      dbl.setQuery(m_queryText.getText());
      dbl.setKeys(m_keyText.getText());
      if (m_dbProps.getText() != null && m_dbProps.getText().length() > 0) {
        dbl.setCustomPropsFile(new File(m_dbProps.getText()));
      }
    }
    
    return update;
  }

View Full Code Here

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