wxDbGridTableBase

You can view a database table in a grid using this class.

If you are deriving your own wxDbTable subclass for your table , then you may consider overriding GetCol() and SetCol() to provide calculated fields. This does work but care should be taken when using wxDbGridTableBase in this way.

The constructor and AssignDbTable() call allows you to specify the ownership if the wxDbTable object pointer. If you tell wxGridTableBase to take ownership , it will delete the passed wxDbTable when an new on is assigned or wxGridTableBase's destructor is called. However no checks for aliasing are done so Assign(table,..,true); Assign(table,..,true); is an error. If you need to requery an table object the preferred way is that the client keeps ownership.

Derived From

wxGridTableBase

Include files

<wx/dbgrid.h>

Example

	// First step, let's define wxDbTable
	int numColumns = 2;
	wxDbTable *table = new wxDbTable (db, tblName, numColumns);
	int int_var;
	wxChar string_name[255];
	table->SetColDef (0, "column 0", DB_DATA_TYPE_INTEGER, &int_var,
			SQL_C_LONG, sizeof(int_var), true);
	table->SetColDef (1, "column 1", DB_DATA_TYPE_VARCHAR, &string_name,
			SQL_C_LONG, sizeof(string_name), false);

    // now let's define columns in the grid

    // first way to do it
    wxDbGridColInfo *columns;
    columns = new wxDbGridColInfo(0, wxGRID_VALUE_LONG, "first column",
              new wxDbGridColInfo(1, wxGRID_VALUE_STRING, "second column",
              NULL);

    // second way to do it
    wxDbGridColInfo *columns;
    // first column is special
    columns = new wxDbGridColInfo(0, wxGRID_VALUE_LONG, "first column", NULL);
    // all the rest
    columns->AddColInfo (1, wxGRID_VALUE_STRING, "second column");

    // second way may be better when columns are not known at compile time

    // now, let's open the table and make a Query()
    table->Open();
    // this step is very important
    table->SetRowMode (wxDbTable::WX_ROW_MODE_QUERY);
    // in the grid we will see only the rows of the result query
    m_dbTable->Query();

    wxDbGridTableBase *dbgrid = new wxDbGridTableBase(table, columns, wxUSE_QUERY, true);
    delete columns;  // not needed anymore
    wxGrid *grid = new wxGrid ( ... );
    grid->SetTable(dbgrid, true);
    grid->Fit();

Include files

<wx/dbgrid.h>

Helper classes and data structures



wxDbGridTableBase::wxDbGridTableBase



wxDbGridTableBase(wxDbTable * tab, wxDbGridColInfo * ColInfo, int count = wxUSE_QUERY, bool takeOwnership = true)

Constructor.

Parameters

tab
The database table you want to display. Must be opened and queried before display the grid. See the example above.
ColInfo
Columns titles, and other values. See wxDbGridColInfo.
count
You can use a query result set (wxUSE_QUERY, to use wxDbTable::Count(wxDbTable::Count() or you can fix the total number of rows (count >= 0) to display, or specify it if you already know the size in avoid calling

takeOwnership
If true, this class deletes wxDbTable when it stops referring to it, if false application must take care of deleting it.



wxDbGridTableBase::ValidateRow



void ValidateRow(int row)

It ensures that the row data is fetched from the database, and it the wxDbTable local buffer, the row number passed should be the grid row.

Parameters

row
Row where validation must be done.



wxDbGridTableBase::UpdateRow



bool UpdateRow(int row)

If row has changed it forces that row to be written back to the database, however support for detecting whether insert/update is required is currently not in wxDbTable, so this function is currently unsupported.

Parameters

row
Row you want to update.



wxDbGridTableBase::AssignDbTable



bool AssignDbTable(wxDbTable * tab,int count = wxUSE_QUERY, bool takeOwnership = true)

Resets the grid for using with a new database table, but using the same columns definition. This can be useful when re-querying the database and want to see the changes.

Parameters

tab
Database table you want to assign to the grid.
count
Number of rows you want to show or wxUSE_QUERY for using a query.
takeOwnership
If false, user must take care of deleting tab after deleting the wxDbGridTableBase. If true, deletion is made by destructor class.
ymasuda 平成17年11月19日