Quill.d

For more information visit the API docs here.

Quill.d is a data access library for the D programming language that sits on top of DDBC. After getting set up you'll be able to write plain SQL in a file or a string, and run it. Quill.d embraces SQL as a language and does not attempt to abstract the database away. As it turns out, SQL is a pretty good language in which to query a database.

Here are a few high level examples:

Fetch some records

auto models = database.list!(Model, "list.sql")();

where list.sql contains

select * from models;

Fetch a single record

auto model = database.single!(Model, "select.sql")(Variant(4));

where select.sql contains

select * from models where id = ?;

Insert a record

database.execute!(Model, "insert.sql")(Variant("name"));

where insert.sql contains

insert into models(name) values(?);

Getting Started

Add Quill.d to dub.json

{
    ...
    "dependencies": {
        "quill-d": "~>0.1.4"
    }
}

Specify a database configuration to use.

PostgreSQL

Add the PostgreSQL configuration to dub.json

{
    ...
    "subConfigurations": {
        "quill-d": "PostgreSQL"
    }
}

Install PostgreSQL Client

If you don't already have it, install the PostgreSQL client

sudo apt-get install postgresql-client

On Linux you may get an error cannot find -lpq. The linker is having trouble finding the client library. To fix this, you can add a symlink like this:

ln -s /usr/lib/libpq.so.5 /usr/lib/libpq.so

Create a new PostgreSQL client:

import quill;
auto database = new Database("127.0.0.1", to!(ushort)(54320), "testdb", "admin", "password", true);

MySQL

Add the MySQL configuration to dub.json

{
    ...
    "subConfigurations": {
        "quill-d": "MySQL"
    }
}

Create a new MySQL client:

import quill;
auto database = new Database("127.0.0.1", to!(ushort)(33060), "testdb", "admin", "password");

SQLite

Add the SQLite configuration to dub.json

{
    ...
    "subConfigurations": {
        "quill-d": "SQLite"
    }
}

Install SQLite3

If you don't already have it, install SQLite3

sudo apt-get install sqlite3 libsqlite3-dev

Create a new SQLite client:

import quill;
auto database = new Database("/path/to/db.sqlite3");

Specify String Import Path

Quill.d uses string imports to run SQL statements in files embedded in the compiled binary. The paths must be added to dub.json to allow for those files to be imported as strings.

{
    ...
    "stringImportPaths": ["queries"]
}

SQL queries can now be imported and run relative to the queries directory like this:

database.execute!("statement.sql")();

Running Tests

The test suite is a collection of integration tests that actually runs SQL in all of the supported databases. Other than SQLite, you'll have to have a database to connect to. If you do not have a database, you can use Database Quickstart to spin up a server for each supported database. The connection details are in the test here. Once there is a database to connect to, the test suite can be run in all of the supported databases from the command line like this:

dub test

Query Types and Parameters

There are a bunch of overloads that can handle various kinds of queries. They are divided up by the expected return type.

Returns	Method Name
none	execute
many	list
one	single

Parameters

For each return type there can be no parameters, model based parameters, or Variant based parameters.

No Parameters Example

This will execute a SQL statement in queries/statement.sql that returns nothing and takes no parameters:

database.execute!("statement.sql")();

Model Based Parameters

Model based parameters can be used by making a class that has fields that map to the column names in the result and the parameter names in the query. In D, bind is used to specify the name of the parameter or the column name in a result set. In SQL, ?(parameter_name) can be used to match the name of the field or the value of bind.

Given a class like this:

class Model
{
    int id;
    @(bind("name")) string name;
}
auto model = new Model();
model.name = "value";

It can map the fields of the class into a query like this:

database.execute!("statement.sql")(model);

where statement.sql looks like this:

insert into models(name) values(?(name));

It can also map the column names from the result of a query like this:

auto models = database.list!("statement.sql")();

where statement.sql looks like this:

select id, name from models;

Variant Based Parameters

Variant based parameters are ordered parameters that can be of any type.

Given a class like this:

class Model
{
    int id;
    @(bind("name")) string name;
}

A Variant or array of Variant will map to each parameter

auto model = database.single!("statement.sql")(Variant(4));

where statement.sql looks like this:

select * from models where id = ?;

Ignoring Properties

Properties that are not public or include the @omit attribute will be ignored. Given the following class, both name and ignored will be omitted.

class Model
{
    int id;
    protected string name;
    @omit string ignored;
}

More Examples

There are a ton more examples in the test and doc comments of database.d.

License and Copyright

See license