Interface Cursor

public interface Cursor

The Cursor interface is used to iterate over the results returned from a database query. IMPORTANT: Notice that some methods might not be supported on all platforms!

There is more thorough coverage of the Database API here.

The sample code below presents a Database Explorer tool that allows executing arbitrary SQL and viewing the tabular results:

Toolbar.setGlobalToolbar(true);
Style s = UIManager.getInstance().getComponentStyle("TitleCommand");
FontImage icon = FontImage.createMaterial(FontImage.MATERIAL_QUERY_BUILDER, s);
Form hi = new Form("SQL Explorer", new BorderLayout());
hi.getToolbar().addCommandToRightBar("", icon, (e) -> {
    TextArea query = new TextArea(3, 80);
    Command ok = new Command("Execute");
    Command cancel = new Command("Cancel");
    if(Dialog.show("Query", query, ok, cancel) == ok) {
        Database db = null;
        Cursor cur = null;
        try {
            db = Display.getInstance().openOrCreate("MyDB.db");
            if(query.getText().startsWith("select")) {
                cur = db.executeQuery(query.getText());
                int columns = cur.getColumnCount();
                hi.removeAll();
                if(columns > 0) {
                    boolean next = cur.next();
                    if(next) {
                        ArrayList data = new ArrayList<>();
                        String[] columnNames = new String[columns];
                        for(int iter = 0 ; iter

@author Chen

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    close()
    Close the cursor and release its resources
    boolean
    first()
    Move the cursor to the first row.
    int
    getColumnCount()
    Returns the column count
    int
    getColumnIndex(String columnName)
    Returns the zero-based index for a given column name.
    String
    getColumnName(int columnIndex)
    Returns the column name at a given zero-based column index.
    int
    getPosition()
    Returns the current Cursor position.
    Row
    getRow()
    Get the Row data Object.
    boolean
    last()
    Move the cursor to the last row.
    boolean
    next()
    Moves the cursor to the next row.
    boolean
    position(int row)
    Move the cursor to an absolute row position
    boolean
    prev()
    Moves the cursor to the previous row.

  • Method Details

    • first

      boolean first() throws IOException

      Move the cursor to the first row.

      If cursor provides forward-only navigation and is positioned after the first row then calling first() method would throw a IOException.

      Returns

      true if succeeded

      Throws
      • IOException
      Throws:
      IOException

    • last

      boolean last() throws IOException

      Move the cursor to the last row.

      Returns

      true if succeeded

      Throws
      • IOException
      Throws:
      IOException

    • next

      boolean next() throws IOException

      Moves the cursor to the next row. Calling next() method the first time will position cursor on the first.

      Returns

      true if succeeded

      Throws
      • IOException
      Throws:
      IOException

    • prev

      boolean prev() throws IOException

      Moves the cursor to the previous row. If cursor is forward type then calling prev() would throw a IOException.

      Returns

      true if succeeded

      Throws
      • IOException
      Throws:
      IOException

    • getColumnIndex

      int getColumnIndex(String columnName) throws IOException

      Returns the zero-based index for a given column name. Note that columns meta information is available only after navigation to the first row

      Parameters
      • columnName: the name of the column.
      Returns

      the index of the column

      Throws
      • IOException
      Throws:
      IOException

    • getColumnName

      String getColumnName(int columnIndex) throws IOException

      Returns the column name at a given zero-based column index. Note that columns meta information is available only after navigation to the first row

      Parameters
      • columnIndex: the index of the column
      Returns

      the name of the column

      Throws
      • IOException
      Throws:
      IOException

    • getColumnCount

      int getColumnCount() throws IOException

      Returns the column count

      Returns

      the column count

      Throws
      • IOException
      Throws:
      IOException

    • getPosition

      int getPosition() throws IOException

      Returns the current Cursor position.

      Returns

      the cursor position

      Throws
      • IOException
      Throws:
      IOException

    • position

      boolean position(int row) throws IOException

      Move the cursor to an absolute row position

      Parameters
      • row: position to move to
      Returns

      true if succeeded

      Throws
      • IOException
      Throws:
      IOException

    • close

      void close() throws IOException

      Close the cursor and release its resources

      Throws
      • IOException
      Throws:
      IOException

    • getRow

      Row getRow() throws IOException

      Get the Row data Object.

      Returns

      a Row Object

      Throws
      • IOException
      Throws:
      IOException