d2sqlite3 0.2.0

d2sqlite3

This is a small wrapper around for SQLite (version 3) for the D programming language. It provides a simple "object-oriented" interface to the SQLite database engine.

Features

1. Database is wrapper around a database connection. The connection is open at the time of its creation and it is automatically closed when no more references exist. Possibility to enable a shared cache.
2. Database has facility functions create new functions, aggregates or collations.
3. Query is a wrapper around prepared statements and their results, with functionality to:
   • bind parameters: params.bind
   • iterate on result rows with an InputRange interface: rows
   • convert column to D type: get

Synopsis

// Open a database in memory.
Database db;
try
{
    db = Database(":memory:");
}
catch (SqliteException e)
{
    // Error creating the database
    assert(false, "Error: " ~ e.msg);
}

// Create a table.
try
{
    db.execute(
        "CREATE TABLE person (
            id INTEGER PRIMARY KEY,
            last_name TEXT NOT NULL,
            first_name TEXT,
            score REAL,
            photo BLOB
         )"
    );
}
catch (SqliteException e)
{
    // Error creating the table.
    assert(false, "Error: " ~ e.msg);
}

// Populate the table.
try
{
    auto query = db.query(
        "INSERT INTO person (last_name, first_name, score, photo)
         VALUES (:last_name, :first_name, :score, :photo)"
    );
    
    // Bind everything with chained calls to params.bind().
    query.params.bind(":last_name", "Smith")
                .bind(":first_name", "John")
                .bind(":score", 77.5);
    ubyte[] photo = cast(ubyte[]) "..."; // Store the photo as raw array of data.
    query.params.bind(":photo", photo);
    query.execute();
    
    query.reset(); // Need to reset the query after execution.
    query.params.bind(":last_name", "Doe")
                .bind(":first_name", "John")
                .bind(3, null) // Use of index instead of name.
                .bind(":photo", null);
    query.execute();
}
catch (SqliteException e)
{
    // Error executing the query.
    assert(false, "Error: " ~ e.msg);
}
assert(db.totalChanges == 2); // Two 'persons' were inserted.

// Reading the table
try
{
    // Count the Johns in the table.
    auto query = db.query("SELECT count(*) FROM person WHERE first_name == 'John'");
    assert(query.rows.front[0].get!int() == 2);
    
    // Fetch the data from the table.
    query = db.query("SELECT * FROM person");
    foreach (row; query.rows)
    {
        // "id" should be the column at index 0:
        auto id = row[0].get!int();
        // Some conversions are possible with the method as():
        auto name = format("%s, %s", row["last_name"].get!string(), row["first_name"].get!(char[])());
        // The score can be NULL, so provide 0 (instead of NAN) as a default value to replace NULLs:
        auto score = row["score"].get!real(0.0);
        // Use of opDispatch with column name:
        auto photo = row.photo.get!(ubyte[])();
        
        // ... and use all these data!
    }
}
catch (SqliteException e)
{
    // Error reading the database.
    assert(false, "Error: " ~ e.msg);
}

License: BSL 1.0

Copyright 2011-14, Nicolas Sicard