urho3d/bin/Data/Scripts/41_DatabaseDemo.as

/// Database demo. This sample demonstrates how to use database subsystem to connect to a database and execute adhoc SQL statements.

#include "Scripts/Utilities/Sample.as"

DbConnection@ connection;
uint row;
uint maxRows = 50;

void Start()
{
    // Execute the common startup for samples
    SampleStart();

    // Disable default execution of AngelScript from the console
    script.executeConsoleCommands = false;

    // Subscribe to console commands and the frame update
    SubscribeToEvent("ConsoleCommand", "HandleConsoleCommand");
    SubscribeToEvent("Update", "HandleUpdate");

    // Subscribe key down event
    SubscribeToEvent("KeyDown", "HandleEscKeyDown");

    // Hide logo to make room for the console
    SetLogoVisible(false);

    // Show the console by default, make it large
    console.numRows = graphics.height / 16;
    console.numBufferedRows = 2 * console.numRows;
    console.commandInterpreter = "ScriptEventInvoker";
    console.visible = true;
    console.closeButton.visible = false;

    // Show OS mouse cursor
    input.mouseVisible = true;

    // Set the mouse mode to use in the sample
    SampleInitMouseMode(MM_FREE);

    // Open the operating system console window (for stdin / stdout) if not open yet
    // Do not open in fullscreen, as this would cause constant device loss
    if (!graphics.fullscreen)
        OpenConsoleWindow();

    // In general, the connection string is really the only thing that need to be changed when switching underlying database API
    //   and that when using ODBC API then the connection string must refer to an already installed ODBC driver
    // Although it has not been tested yet but the ODBC API should be able to interface with any vendor provided ODBC drivers
    // In this particular demo, however, when using ODBC API then the SQLite-ODBC driver need to be installed
    // The SQLite-ODBC driver can be built from source downloaded from http://www.ch-werner.de/sqliteodbc/
    // You can try to install other ODBC driver and modify the connection string below to match your ODBC driver
    // Both DSN and DSN-less connection string should work
    // The ODBC API, i.e. URHO3D_DATABASE_ODBC build option, is only available for native (including RPI) platforms
    //   and it is designed for development of game server connecting to ODBC-compliant databases in mind

    // This demo will always work when using SQLite API as the SQLite database engine is embedded inside Urho3D game engine
    //   and this is also the case when targeting Web platform

    // We could have used #ifdef to init the connection string during compile time, but below shows how it is done during runtime
    // The "URHO3D_DATABASE_ODBC" compiler define is set when URHO3D_DATABASE_ODBC build option is enabled
    // Connect to a temporary in-memory SQLite database
    connection = database.Connect(DBAPI == DBAPI_ODBC ? "Driver=SQLite3;Database=:memory:" : "file://");

    // Subscribe to database cursor event to loop through query resultset
    SubscribeToEvent("DbCursor", "HandleDbCursor");

    // Show instruction
    Print("This demo connects to temporary in-memory database.\n"
    "All the tables and their data will be lost after exiting the demo.\n"
    "Enter a valid SQL statement in the console input and press Enter to execute.\n"
    "Enter 'get/set maxrows [number]' to get/set the maximum rows to be printed out.\n"
    "Enter 'get/set connstr [string]' to get/set the database connection string and establish a new connection to it.\n"
    "Enter 'quit' or 'exit' to exit the demo.\n"
    "For example:\n ");
    HandleInput("create table tbl1(col1 varchar(10), col2 smallint)");
    HandleInput("insert into tbl1 values('Hello', 10)");
    HandleInput("insert into tbl1 values('World', 20)");
    HandleInput("select * from tbl1");
}

void HandleConsoleCommand(StringHash eventType, VariantMap& eventData)
{
    if (eventData["Id"].GetString() == "ScriptEventInvoker")
        HandleInput(eventData["Command"].GetString());
}

void HandleUpdate(StringHash eventType, VariantMap& eventData)
{
    // Check if there is input from stdin
    String input = GetConsoleInput();
    if (input.length > 0)
        HandleInput(input);
}

void HandleEscKeyDown(StringHash eventType, VariantMap& eventData)
{
    // Unlike the other samples, exiting the engine when ESC is pressed instead of just closing the console
    if (eventData["Key"].GetInt() == KEY_ESCAPE)
        engine.Exit();
}

void HandleDbCursor(StringHash eventType, VariantMap& eventData)
{
    // In a real application the P_SQL can be used to do the logic branching in a shared event handler
    // However, this is not required in this sample demo
    uint numCols = eventData["NumCols"].GetUInt();
    Array<Variant>@ colValues = eventData["ColValues"].GetVariantVector();
    Array<String>@ colHeaders = eventData["ColHeaders"].GetStringVector();

    // In this sample demo we just use db cursor to dump each row immediately so we can filter out the row to conserve memory
    // In a real application this can be used to perform the client-side filtering logic
    eventData["Filter"] = true;
    // In this sample demo we abort the further cursor movement when maximum rows being dumped has been reached
    eventData["Abort"] = ++row >= maxRows;

    for (uint i = 0; i < numCols; ++i)
        Print("Row #" + row + ": " + colHeaders[i] + " = " + colValues[i].ToString());
}

void HandleInput(const String&in input)
{
    // Echo input string to stdout
    Print(input);
    row = 0;
    if (input == "quit" || input == "exit")
        engine.Exit();
    else if (input.StartsWith("set") || input.StartsWith("get"))
    {
        // We expect a key/value pair for 'set' command
        Array<String> tokens = input.Substring(3).Split(' ');
        String setting = tokens.length > 0 ? tokens[0] : "";
        if (input.StartsWith("set") && tokens.length > 1)
        {
            if (setting == "maxrows")
                maxRows = Max(tokens[1].ToUInt(), 1);
            else if (setting == "connstr") {
                String newConnectionString(input.Substring(input.Find(" ", input.Find("connstr")) + 1));
                DbConnection@ newConnection = database.Connect(newConnectionString);
                if (newConnection !is null)
                {
                    database.Disconnect(connection);
                    connection = newConnection;
                }
            }
        }
        if (tokens.length > 0)
        {
            if (setting == "maxrows")
                Print("maximum rows is set to " + maxRows);
            else if (setting == "connstr")
                Print("connection string is set to " + connection.connectionString);
            else
                Print("Unrecognized setting: " + setting);
        }
        else
            Print("Missing setting paramater. Recognized settings are: maxrows, connstr");
    }
    else
    {
        // In this sample demo we use the dbCursor event to loop through each row as it is being fetched
        // Regardless of this event is being used or not, all the fetched rows will be made available in the DbResult object,
        //   unless the dbCursor event handler has instructed to filter out the fetched row from the final result
        DbResult result = connection.Execute(input, true);

        // Number of affected rows is only meaningful for DML statements like insert/update/delete
        if (result.numAffectedRows != -1)
            Print("Number of affected rows: " + result.numAffectedRows);
    }
    Print(" ");
}

// Create XML patch instructions for screen joystick layout specific to this sample app
String patchInstructions =
        "<patch>" +
        "    <add sel=\"/element/element[./attribute[@name='Name' and @value='Button2']]\">" +
        "        <attribute name=\"Is Visible\" value=\"false\" />" +
        "    </add>" +
        "    <add sel=\"/element/element[./attribute[@name='Name' and @value='Hat0']]\">" +
        "        <attribute name=\"Is Visible\" value=\"false\" />" +
        "    </add>" +
        "</patch>";