feature: add Microsoft SQL Server database support

can be used via the pdo_dblib or pdo_odbc extensions.
requires Microsoft SQL Server 2016 or later.

* add schema/migrations
* add database provider
* add setup check for pdo module needed by selected driver (dblib/odbc)
* add default config doc

app/Schema/Mssql.php

@@ -0,0 +1,723 @@
+<?php
+
+namespace Schema;
+
+require_once __DIR__.'/Migration.php';
+
+use PDO;
+use Kanboard\Core\Security\Token;
+use Kanboard\Core\Security\Role;
+
+const VERSION = 1;
+
+function version_1(PDO $pdo)
+{
+    // create tables
+    $pdo->exec("
+        CREATE TABLE dbo.users (
+          id int identity PRIMARY KEY
+          , username nvarchar(255) NOT NULL
+          , password nvarchar(255)
+          , is_ldap_user bit DEFAULT 0
+          , name nvarchar(255)
+          , email nvarchar(255)
+          , google_id nvarchar(255)
+          , github_id nvarchar(30)
+          , notifications_enabled bit DEFAULT 0
+          , timezone nvarchar(50) DEFAULT N''
+          , language nvarchar(11) DEFAULT N''
+          , disable_login_form bit DEFAULT 0
+          , twofactor_activated bit DEFAULT 0
+          , twofactor_secret char(16)
+          , token nvarchar(255) DEFAULT N''
+          , notifications_filter int DEFAULT 4
+          , nb_failed_login int DEFAULT 0
+          , lock_expiration_date bigint DEFAULT 0
+          , gitlab_id int
+          , role nvarchar(25) NOT NULL
+          , is_active bit DEFAULT 1
+          , avatar_path nvarchar(255)
+          , api_access_token nvarchar(255)
+          , filter nvarchar(max) DEFAULT N''
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.projects (
+          id int identity PRIMARY KEY
+          , name nvarchar(max) NOT NULL
+          , is_active bit DEFAULT 1
+          , token nvarchar(255)
+          , last_modified bigint DEFAULT 0
+          , is_public bit DEFAULT 0
+          , is_private bit DEFAULT 0
+          , description nvarchar(max)
+          , identifier nvarchar(50) DEFAULT N''
+          , start_date nvarchar(10) DEFAULT ''
+          , end_date nvarchar(10) DEFAULT ''
+          , owner_id int DEFAULT 0
+          , priority_default int DEFAULT 0
+          , priority_start int DEFAULT 0
+          , priority_end int DEFAULT 3
+          , email nvarchar(max)
+          , predefined_email_subjects nvarchar(max)
+          , per_swimlane_task_limits bit DEFAULT 0 NOT NULL
+          , task_limit int DEFAULT 0
+          , enable_global_tags bit DEFAULT 1 NOT NULL
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.columns (
+          id int identity PRIMARY KEY
+          , title nvarchar(255) NOT NULL
+          , position int
+          , project_id int NOT NULL
+          , task_limit int DEFAULT 0
+          , description nvarchar(max)
+          , hide_in_dashboard bit DEFAULT 0 NOT NULL
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE NO ACTION /* projects_cascade_delete_trigger */
+          , UNIQUE (title, project_id)
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.project_has_users (
+          project_id int NOT NULL
+          , user_id int NOT NULL
+          , role nvarchar(255) NOT NULL
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE CASCADE
+          , FOREIGN KEY(user_id) REFERENCES dbo.users(id) ON DELETE CASCADE
+          , UNIQUE(project_id, user_id)
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.actions (
+            id int identity PRIMARY KEY
+          , project_id int NOT NULL
+          , event_name nvarchar(max) NOT NULL
+          , action_name nvarchar(max) NOT NULL
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.action_has_params (
+            id int identity PRIMARY KEY
+          , action_id int NOT NULL
+          , name nvarchar(max) NOT NULL
+          , value nvarchar(max) NOT NULL
+          , FOREIGN KEY(action_id) REFERENCES dbo.actions(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.remember_me (
+            id int identity PRIMARY KEY
+          , user_id int NOT NULL
+          , ip nvarchar(45)
+          , user_agent nvarchar(255)
+          , token nvarchar(255)
+          , sequence nvarchar(255)
+          , expiration int
+          , date_creation bigint
+          , FOREIGN KEY(user_id) REFERENCES dbo.users(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.last_logins (
+            id int identity PRIMARY KEY
+          , auth_type nvarchar(25)
+          , user_id int NOT NULL
+          , ip nvarchar(45)
+          , user_agent nvarchar(255)
+          , date_creation bigint
+          , FOREIGN KEY(user_id) REFERENCES dbo.users(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.project_has_categories (
+            id int identity PRIMARY KEY
+          , name nvarchar(255) NOT NULL
+          , project_id int NOT NULL
+          , description nvarchar(max)
+          , color_id nvarchar(50)
+          , UNIQUE (project_id, name)
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.swimlanes (
+            id int identity PRIMARY KEY
+          , name nvarchar(848) NOT NULL  /* max size for unique index */
+          , position int DEFAULT 1
+          , is_active bit DEFAULT 1
+          , project_id int NOT NULL
+          , description nvarchar(max)
+          , task_limit int DEFAULT 0
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE NO ACTION /* projects_cascade_delete_trigger */
+          , UNIQUE (name, project_id)
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.tasks
+        (
+            id                   int identity PRIMARY KEY
+          , title                nvarchar(max) NOT NULL
+          , description          nvarchar(max)
+          , date_creation        bigint
+          , color_id             nvarchar(255)
+          , project_id           int NOT NULL
+          , column_id            int NOT NULL
+          , owner_id             int DEFAULT 0
+          , position             int
+          , is_active            bit DEFAULT 1
+          , date_completed       bigint
+          , score                int
+          , date_due             bigint
+          , category_id          int DEFAULT 0
+          , creator_id           int DEFAULT 0
+          , date_modification    int DEFAULT 0
+          , reference            nvarchar(max) DEFAULT ''
+          , date_started         bigint
+          , time_spent           float DEFAULT 0
+          , time_estimated       float DEFAULT 0
+          , swimlane_id          int NOT NULL
+          , date_moved           bigint DEFAULT 0
+          , recurrence_status    int DEFAULT 0 NOT NULL
+          , recurrence_trigger   int DEFAULT 0 NOT NULL
+          , recurrence_factor    int DEFAULT 0 NOT NULL
+          , recurrence_timeframe int DEFAULT 0 NOT NULL
+          , recurrence_basedate  int DEFAULT 0 NOT NULL
+          , recurrence_parent    int
+          , recurrence_child     int
+          , priority             int DEFAULT 0
+          , external_provider    nvarchar(255)
+          , external_uri         nvarchar(255)
+          , FOREIGN KEY (project_id) REFERENCES dbo.projects(id) ON DELETE NO ACTION /* projects_cascade_delete_trigger */
+          , FOREIGN KEY (column_id) REFERENCES dbo.columns(id) ON DELETE NO ACTION /* columns_cascade_delete_trigger */
+          , FOREIGN KEY (swimlane_id) REFERENCES dbo.swimlanes(id) ON DELETE NO ACTION /* swimlanes_cascade_delete_trigger */
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.task_has_files (
+            id int identity PRIMARY KEY
+          , name nvarchar(max) NOT NULL
+          , path nvarchar(max)
+          , is_image bit DEFAULT 0
+          , task_id int NOT NULL
+          , date bigint NOT NULL DEFAULT 0
+          , user_id int NOT NULL DEFAULT 0
+          , size int NOT NULL DEFAULT 0
+          , FOREIGN KEY(task_id) REFERENCES dbo.tasks(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.subtasks (
+            id int identity PRIMARY KEY
+          , title nvarchar(max) NOT NULL
+          , status smallint DEFAULT 0
+          , time_estimated float DEFAULT 0
+          , time_spent float DEFAULT 0
+          , task_id int NOT NULL
+          , user_id int
+          , position int DEFAULT 1
+          , FOREIGN KEY(task_id) REFERENCES dbo.tasks(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.user_has_notifications (
+            user_id int NOT NULL
+          , project_id int NOT NULL
+          , FOREIGN KEY(user_id) REFERENCES dbo.users(id) ON DELETE CASCADE
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE CASCADE
+          , UNIQUE(project_id, user_id)
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.settings (
+            [option] nvarchar(100) PRIMARY KEY
+          , value nvarchar(max) DEFAULT ''
+          , changed_by int DEFAULT 0 NOT NULL
+          , changed_on int DEFAULT 0 NOT NULL
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.project_daily_column_stats (
+            id int identity PRIMARY KEY
+          , day nchar(10) NOT NULL
+          , project_id int NOT NULL
+          , column_id int NOT NULL
+          , total int NOT NULL DEFAULT 0
+          , score int NOT NULL DEFAULT 0
+          , FOREIGN KEY(column_id) REFERENCES dbo.columns(id) ON DELETE CASCADE
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE NO ACTION /* projects_cascade_delete_trigger */
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.subtask_time_tracking (
+            id int identity PRIMARY KEY
+          , user_id int NOT NULL
+          , subtask_id int NOT NULL
+          , [start] bigint DEFAULT 0
+          , [end] bigint DEFAULT 0
+          , time_spent real DEFAULT 0
+          , FOREIGN KEY(user_id) REFERENCES dbo.users(id) ON DELETE CASCADE
+          , FOREIGN KEY(subtask_id) REFERENCES dbo.subtasks(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.links (
+            id int identity PRIMARY KEY
+          , label nvarchar(255) NOT NULL
+          , opposite_id int DEFAULT 0
+          , UNIQUE(label)
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.task_has_links (
+            id int identity PRIMARY KEY
+          , link_id int NOT NULL
+          , task_id int NOT NULL
+          , opposite_task_id int NOT NULL
+          , FOREIGN KEY(link_id) REFERENCES dbo.links(id) ON DELETE CASCADE
+          , FOREIGN KEY(task_id) REFERENCES dbo.tasks(id) ON DELETE CASCADE
+          , FOREIGN KEY(opposite_task_id) REFERENCES dbo.tasks(id) ON DELETE NO ACTION /* Handled in tasks_cascade_delete_trigger */
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.transitions (
+            id int identity PRIMARY KEY
+          , user_id int NOT NULL
+          , project_id int NOT NULL
+          , task_id int NOT NULL
+          , src_column_id int NOT NULL
+          , dst_column_id int NOT NULL
+          , date bigint NOT NULL
+          , time_spent int DEFAULT 0
+          , FOREIGN KEY(src_column_id) REFERENCES dbo.columns(id) ON DELETE NO ACTION  /* columns_cascade_delete_trigger */
+          , FOREIGN KEY(dst_column_id) REFERENCES dbo.columns(id) ON DELETE NO ACTION  /* columns_cascade_delete_trigger */
+          , FOREIGN KEY(user_id) REFERENCES dbo.users(id) ON DELETE CASCADE
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE NO ACTION /* projects_cascade_delete_trigger */
+          , FOREIGN KEY(task_id) REFERENCES dbo.tasks(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.currencies (
+            currency nvarchar(3) NOT NULL UNIQUE
+          , rate REAL DEFAULT 0
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.comments (
+            id int identity PRIMARY KEY
+          , task_id int NOT NULL
+          , user_id int DEFAULT 0
+          , date_creation bigint NOT NULL
+          , comment nvarchar(max) NOT NULL
+          , reference nvarchar(max) DEFAULT N''
+          , date_modification bigint
+          , FOREIGN KEY(task_id) REFERENCES dbo.tasks(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.project_daily_stats (
+            id int identity PRIMARY KEY
+          , day nchar(10) NOT NULL
+          , project_id int NOT NULL
+          , avg_lead_time int NOT NULL DEFAULT 0
+          , avg_cycle_time int NOT NULL DEFAULT 0
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.plugin_schema_versions (
+            plugin nvarchar(80) NOT NULL PRIMARY KEY
+          , version int NOT NULL DEFAULT 0
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.custom_filters (
+            id int identity PRIMARY KEY
+          , filter nvarchar(max) NOT NULL
+          , project_id int NOT NULL
+          , user_id int NOT NULL
+          , name nvarchar(max) NOT NULL
+          , is_shared bit DEFAULT 0
+          , append bit DEFAULT 0
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.user_has_unread_notifications (
+            id int identity PRIMARY KEY
+          , user_id int NOT NULL
+          , date_creation bigint NOT NULL
+          , event_name nvarchar(max) NOT NULL
+          , event_data nvarchar(max) NOT NULL
+          , FOREIGN KEY(user_id) REFERENCES dbo.users(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.user_has_notification_types (
+            id int identity PRIMARY KEY
+          , user_id int NOT NULL
+          , notification_type nvarchar(50)
+          , FOREIGN KEY(user_id) REFERENCES dbo.users(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.project_has_notification_types (
+            id int identity PRIMARY KEY
+          , project_id int NOT NULL
+          , notification_type nvarchar(50) NOT NULL
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE CASCADE
+          , UNIQUE(project_id, notification_type)
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.user_has_metadata (
+            user_id int NOT NULL
+          , name nvarchar(50) NOT NULL
+          , value nvarchar(255) DEFAULT ''
+          , changed_by int DEFAULT 0 NOT NULL
+          , changed_on int DEFAULT 0 NOT NULL /* TODO: should be bigint?? */
+          , FOREIGN KEY(user_id) REFERENCES dbo.users(id) ON DELETE CASCADE
+          , UNIQUE(user_id, name)
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.project_has_metadata (
+            project_id int NOT NULL
+          , name nvarchar(50) NOT NULL
+          , value nvarchar(255) DEFAULT ''
+          , changed_by int DEFAULT 0 NOT NULL
+          , changed_on int DEFAULT 0 NOT NULL /* TODO: should be bigint?? */
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE CASCADE
+          , UNIQUE(project_id, name)
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.task_has_metadata (
+            task_id int NOT NULL
+          , name nvarchar(50) NOT NULL
+          , value nvarchar(255) DEFAULT ''
+          , changed_by int DEFAULT 0 NOT NULL
+          , changed_on int DEFAULT 0 NOT NULL /* TODO: should be bigint?? */
+          , FOREIGN KEY(task_id) REFERENCES dbo.tasks(id) ON DELETE CASCADE
+          , UNIQUE(task_id, name)
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.groups (
+            id int identity PRIMARY KEY
+          , external_id nvarchar(255) DEFAULT ''
+          , name nvarchar(850) NOT NULL UNIQUE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.group_has_users (
+            group_id int NOT NULL
+          , user_id int NOT NULL
+          , FOREIGN KEY(group_id) REFERENCES dbo.groups(id) ON DELETE CASCADE
+          , FOREIGN KEY(user_id) REFERENCES dbo.users(id) ON DELETE CASCADE
+          , UNIQUE(group_id, user_id)
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.project_has_groups (
+            group_id int NOT NULL
+          , project_id int NOT NULL
+          , role nvarchar(255) NOT NULL
+          , FOREIGN KEY(group_id) REFERENCES dbo.groups(id) ON DELETE CASCADE
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE CASCADE
+          , UNIQUE(group_id, project_id)
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.password_reset (
+            token nvarchar(80) PRIMARY KEY
+          , user_id int NOT NULL
+          , date_expiration int NOT NULL /* TODO: bigint?? */
+          , date_creation int NOT NULL /* TODO: bigint?? */
+          , ip nvarchar(45) NOT NULL
+          , user_agent nvarchar(255) NOT NULL
+          , is_active bit NOT NULL
+          , FOREIGN KEY(user_id) REFERENCES dbo.users(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.task_has_external_links (
+            id int identity PRIMARY KEY
+          , link_type nvarchar(100) NOT NULL
+          , dependency nvarchar(100) NOT NULL
+          , title nvarchar(max) NOT NULL
+          , url nvarchar(max) NOT NULL
+          , date_creation int NOT NULL /* TODO: bigint?? */
+          , date_modification int NOT NULL /* TODO: bigint?? */
+          , task_id int NOT NULL
+          , creator_id int DEFAULT 0
+          , FOREIGN KEY(task_id) REFERENCES dbo.tasks(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.project_has_files (
+            id int identity PRIMARY KEY
+          , project_id int NOT NULL
+          , name nvarchar(max) NOT NULL
+          , path nvarchar(max) NOT NULL
+          , is_image bit DEFAULT 0
+          , size int DEFAULT 0 NOT NULL
+          , user_id int DEFAULT 0 NOT NULL
+          , date int DEFAULT 0 NOT NULL /* TODO: bigint?? */
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.tags (
+            id int identity PRIMARY KEY
+          , name nvarchar(255) NOT NULL
+          , project_id int NOT NULL
+          , color_id nvarchar(50) DEFAULT NULL
+          , UNIQUE(project_id, name)
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.task_has_tags (
+            task_id int NOT NULL
+          , tag_id int NOT NULL
+          , FOREIGN KEY(task_id) REFERENCES dbo.tasks(id) ON DELETE CASCADE
+          , FOREIGN KEY(tag_id) REFERENCES dbo.tags(id) ON DELETE CASCADE
+          , UNIQUE(tag_id, task_id)
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.project_has_roles (
+            role_id int identity PRIMARY KEY
+          , role nvarchar(255) NOT NULL
+          , project_id int NOT NULL
+          , UNIQUE(project_id, role)
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.column_has_move_restrictions (
+            restriction_id int identity PRIMARY KEY
+          , project_id int NOT NULL
+          , role_id int NOT NULL
+          , src_column_id int NOT NULL
+          , dst_column_id int NOT NULL
+          , only_assigned bit DEFAULT 0
+          , UNIQUE(role_id, src_column_id, dst_column_id)
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE NO ACTION /* projects_cascade_delete_trigger */
+          , FOREIGN KEY(role_id) REFERENCES dbo.project_has_roles(role_id) ON DELETE CASCADE
+          , FOREIGN KEY(src_column_id) REFERENCES dbo.columns(id) ON DELETE NO ACTION /* columns_cascade_delete_trigger */
+          , FOREIGN KEY(dst_column_id) REFERENCES dbo.columns(id) ON DELETE NO ACTION /* columns_cascade_delete_trigger */
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.project_role_has_restrictions (
+            restriction_id int identity PRIMARY KEY
+          , project_id int NOT NULL
+          , role_id int NOT NULL
+          , [rule] nvarchar(255) NOT NULL
+          , UNIQUE(role_id, [rule])
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE NO ACTION /* projects_cascade_delete_trigger */
+          , FOREIGN KEY(role_id) REFERENCES dbo.project_has_roles(role_id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.column_has_restrictions (
+            restriction_id int identity PRIMARY KEY
+          , project_id int NOT NULL
+          , role_id int NOT NULL
+          , column_id int NOT NULL
+          , [rule] nvarchar(255) NOT NULL
+          , UNIQUE(role_id, column_id, [rule])
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE NO ACTION /* projects_cascade_delete_trigger */
+          , FOREIGN KEY(role_id) REFERENCES dbo.project_has_roles(role_id) ON DELETE CASCADE
+          , FOREIGN KEY(column_id) REFERENCES dbo.columns(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.invites (
+            email nvarchar(255) NOT NULL
+          , project_id int NOT NULL
+          , token nvarchar(255) NOT NULL
+          , PRIMARY KEY(email, token)
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.project_activities (
+            id int identity PRIMARY KEY
+          , date_creation bigint NOT NULL
+          , event_name nvarchar(max) NOT NULL
+          , creator_id int NOT NULL
+          , project_id int NOT NULL
+          , task_id int NOT NULL
+          , data nvarchar(max)
+          , FOREIGN KEY(creator_id) REFERENCES dbo.users(id) ON DELETE CASCADE
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE NO ACTION /* projects_cascade_delete_trigger */
+          , FOREIGN KEY(task_id) REFERENCES dbo.tasks(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.predefined_task_descriptions (
+            id int identity PRIMARY KEY
+          , project_id int NOT NULL
+          , title nvarchar(max) NOT NULL
+          , description nvarchar(max) NOT NULL
+          , FOREIGN KEY(project_id) REFERENCES dbo.projects(id) ON DELETE CASCADE
+        );
+    ");
+    $pdo->exec("
+        CREATE TABLE dbo.sessions (
+            id nvarchar(450) PRIMARY KEY /* max length for primary key */
+          , expire_at int NOT NULL
+          , data nvarchar(max) DEFAULT ''
+        );
+    ");
+
+    // create triggers -- each of which must be in its own batch
+    $pdo->exec("
+        CREATE TRIGGER dbo.columns_cascade_delete_trigger
+        ON dbo.columns INSTEAD OF DELETE
+        AS
+          SET NOCOUNT ON;
+          DELETE dbo.column_has_move_restrictions
+          WHERE src_column_id IN (SELECT id FROM deleted)
+            OR  dst_column_id IN (SELECT id FROM deleted);
+          DELETE dbo.transitions
+          WHERE src_column_id IN (SELECT id FROM deleted)
+            OR  dst_column_id IN (SELECT id FROM deleted);
+          DELETE dbo.tasks
+          WHERE column_id IN (SELECT id FROM deleted);
+          DELETE dbo.columns
+          WHERE id IN (SELECT id FROM deleted);
+    ");
+
+    $pdo->exec("
+        CREATE TRIGGER projects_cascade_delete_trigger
+        ON dbo.projects INSTEAD OF DELETE
+        AS
+          SET NOCOUNT ON;
+          DELETE dbo.column_has_move_restrictions
+          WHERE project_id IN (SELECT id FROM deleted);
+          DELETE dbo.column_has_restrictions
+          WHERE project_id IN (SELECT id FROM deleted);
+          DELETE dbo.columns
+          WHERE project_id IN (SELECT id FROM deleted);
+          DELETE dbo.project_activities
+          WHERE project_id IN (SELECT id FROM deleted);
+          DELETE dbo.project_daily_column_stats
+          WHERE project_id IN (SELECT id FROM deleted);
+          DELETE dbo.project_role_has_restrictions
+          WHERE project_id IN (SELECT id FROM deleted);
+          DELETE dbo.swimlanes
+          WHERE project_id IN (SELECT id FROM deleted);
+          DELETE dbo.tasks
+          WHERE project_id IN (SELECT id FROM deleted);
+          DELETE dbo.transitions
+          WHERE project_id IN (SELECT id FROM deleted);
+          DELETE dbo.projects
+          WHERE id IN (SELECT id FROM deleted);
+    ");
+
+    $pdo->exec("
+        CREATE TRIGGER dbo.swimlanes_cascade_delete_trigger
+        ON dbo.swimlanes INSTEAD OF DELETE
+        AS
+          SET NOCOUNT ON;
+          DELETE dbo.tasks
+          WHERE swimlane_id IN (SELECT id FROM deleted);
+          DELETE dbo.swimlanes
+          WHERE id IN (SELECT id FROM deleted);
+    ");
+
+    $pdo->exec("
+        CREATE TRIGGER dbo.tasks_cascade_delete_trigger
+        ON dbo.tasks INSTEAD OF DELETE
+        AS
+          SET NOCOUNT ON;
+          DELETE dbo.task_has_links
+          WHERE opposite_task_id IN (SELECT id FROM deleted);
+          DELETE dbo.tasks
+          WHERE id IN (SELECT id FROM deleted);
+    ");
+
+    // set defaults
+    $pdo->exec("
+        ALTER TABLE dbo.project_has_users
+        ADD DEFAULT N'" .Role::PROJECT_VIEWER. "' FOR role;
+    ");
+    $pdo->exec("
+        ALTER TABLE dbo.users
+        ADD DEFAULT N'" .Role::APP_USER. "' FOR role;
+    ");
+
+    // insert starting data
+    $aui = $pdo->prepare("INSERT INTO dbo.users (username, password, role) VALUES (?, ?, ?);");
+    $aui->execute(array('admin', \password_hash('admin', PASSWORD_BCRYPT), Role::APP_ADMIN));
+
+    $rq = $pdo->prepare('INSERT INTO dbo.settings ([option],value) VALUES (?, ?);');
+    $rq->execute(array('api_token', Token::getToken()));
+    $rq->execute(array('application_url', defined('KANBOARD_URL') ? KANBOARD_URL : ''));
+    $rq->execute(array('board_highlight_period', defined('RECENT_TASK_PERIOD') ? RECENT_TASK_PERIOD : 48*60*60));
+    $rq->execute(array('board_private_refresh_interval', defined('BOARD_CHECK_INTERVAL') ? BOARD_CHECK_INTERVAL : 10));
+    $rq->execute(array('board_public_refresh_interval', defined('BOARD_PUBLIC_CHECK_INTERVAL') ? BOARD_PUBLIC_CHECK_INTERVAL : 60));
+    $rq->execute(array('webhook_token', Token::getToken()));
+
+    $pdo->exec("
+        INSERT INTO dbo.settings ([option], value) VALUES
+          ('application_currency','USD'),
+          ('application_date_format','m/d/Y'),
+          ('application_language','en_US'),
+          ('application_stylesheet',''),
+          ('application_time_format','H:i'),
+          ('application_timezone','UTC'),
+          ('board_columns',''),
+          ('calendar_project_tasks','date_started'),
+          ('calendar_user_subtasks_time_tracking','0'),
+          ('calendar_user_tasks','date_started'),
+          ('cfd_include_closed_tasks','1'),
+          ('default_color','yellow'),
+          ('integration_gravatar','0'),
+          ('password_reset','1'),
+          ('project_categories',''),
+          ('subtask_restriction','0'),
+          ('subtask_time_tracking','1'),
+          ('webhook_url','')
+        ;
+    ");
+
+    $pdo->exec("
+        SET IDENTITY_INSERT dbo.links ON;
+        INSERT INTO dbo.links (id, label, opposite_id) VALUES
+          (1,'relates to',0),
+          (2,'blocks',3),
+          (3,'is blocked by',2),
+          (4,'duplicates',5),
+          (5,'is duplicated by',4),
+          (6,'is a child of',7),
+          (7,'is a parent of',6),
+          (8,'targets milestone',9),
+          (9,'is a milestone of',8),
+          (10,'fixes',11),
+          (11,'is fixed by',10)
+        ;
+        SET IDENTITY_INSERT dbo.links OFF;
+    ");
+
+    // create indexes
+    $pdo->exec("
+        CREATE UNIQUE INDEX users_username_idx ON dbo.users(username);
+        CREATE UNIQUE INDEX project_daily_column_stats_idx ON dbo.project_daily_column_stats(day, project_id, column_id);
+        CREATE UNIQUE INDEX task_has_links_unique ON dbo.task_has_links(link_id, task_id, opposite_task_id);
+        CREATE UNIQUE INDEX project_daily_stats_idx ON dbo.project_daily_stats(day, project_id);
+        CREATE UNIQUE INDEX user_has_notification_types_user_idx ON dbo.user_has_notification_types(user_id, notification_type);
+
+        CREATE INDEX columns_project_idx ON dbo.columns(project_id);
+        CREATE INDEX swimlanes_project_idx ON dbo.swimlanes(project_id);
+        CREATE INDEX categories_project_idx ON dbo.project_has_categories(project_id);
+        CREATE INDEX subtasks_task_idx ON dbo.subtasks(task_id);
+        CREATE INDEX files_task_idx ON dbo.task_has_files(task_id);
+        CREATE INDEX task_has_links_task_index ON dbo.task_has_links(task_id);
+        CREATE INDEX transitions_task_index ON dbo.transitions(task_id);
+        CREATE INDEX transitions_project_index ON dbo.transitions(project_id);
+        CREATE INDEX transitions_user_index ON dbo.transitions(user_id);
+    ");
+}

app/ServiceProvider/DatabaseProvider.php

@@ -59,6 +59,15 @@ class DatabaseProvider implements ServiceProviderInterface
             case 'postgres':
                 $db = $this->getPostgresInstance();
                 break;
+            case 'dblib':
+                $db = $this->getMssqlInstance();
+                break;
+            case 'mssql':
+                $db = $this->getMssqlInstance();
+                break;
+            case 'odbc':
+                $db = $this->getMssqlInstance();
+                break;
             default:
                 throw new LogicException('Database driver not supported');
         }
@@ -160,4 +169,27 @@ class DatabaseProvider implements ServiceProviderInterface
             'timeout'  => DB_TIMEOUT,
         ));
     }
+
+    /**
+     * Setup the MSSQL database driver
+     *
+     * @access private
+     * @return \PicoDb\Database
+     */
+    private function getMssqlInstance()
+    {
+        require_once __DIR__.'/../Schema/Mssql.php';
+
+        return new Database(array(
+            'driver'   => DB_DRIVER,
+            'hostname' => DB_HOSTNAME,
+            'username' => DB_USERNAME,
+            'password' => DB_PASSWORD,
+            'database' => DB_NAME,
+            'port'     => DB_PORT,
+            'odbc-dsn' => DB_ODBC_DSN,
+            'timeout'  => DB_TIMEOUT,
+            'appname'  => 'Kanboard',
+        ));
+    }
 }

app/check_setup.php

@@ -23,6 +23,14 @@ if (DB_DRIVER === 'postgres' && !extension_loaded('pdo_pgsql')) {
     throw new Exception('PHP extension required: "pdo_pgsql"');
 }
 
+if (DB_DRIVER === 'odbc' && !extension_loaded('pdo_odbc')) {
+    throw new Exception('PHP extension required: "pdo_odbc"');
+}
+
+if (DB_DRIVER === 'dblib' && !extension_loaded('pdo_dblib')) {
+    throw new Exception('PHP extension required: "pdo_dblib"');
+}
+
 // Check other extensions
 foreach (array('gd', 'mbstring', 'hash', 'openssl', 'json', 'hash', 'ctype', 'filter', 'session', 'dom', 'filter', 'SimpleXML', 'xml') as $ext) {
     if (!extension_loaded($ext)) {

app/constants.php

@@ -50,6 +50,7 @@ defined('DB_PASSWORD') or define('DB_PASSWORD', getenv('DB_PASSWORD') ?: '');
 defined('DB_HOSTNAME') or define('DB_HOSTNAME', getenv('DB_HOSTNAME') ?: 'localhost');
 defined('DB_NAME') or define('DB_NAME', getenv('DB_NAME') ?: 'kanboard');
 defined('DB_PORT') or define('DB_PORT', intval(getenv('DB_PORT')) ?: null);
+defined('DB_ODBC_DSN') or define('DB_ODBC_DSN', getenv('DB_ODBC_DSN') ?: 'kanboard');
 defined('DB_SSL_KEY') or define('DB_SSL_KEY', getenv('DB_SSL_KEY') ?: null);
 defined('DB_SSL_CERT') or define('DB_SSL_CERT', getenv('DB_SSL_CERT') ?: null);
 defined('DB_SSL_CA') or define('DB_SSL_CA', getenv('DB_SSL_CA') ?: null);

config.default.php

@@ -66,22 +66,22 @@ define('MAIL_SENDMAIL_COMMAND', '/usr/sbin/sendmail -bs');
 // Do not run the migrations from multiple processes at the same time (example: web page + background worker)
 define('DB_RUN_MIGRATIONS', true);
 
-// Database driver: sqlite, mysql or postgres (sqlite by default)
+// Database driver: sqlite, mysql, postgres, odbc, dblib, or mssql (sqlite by default)
 define('DB_DRIVER', 'sqlite');
 
-// Mysql/Postgres username
+// Database username
 define('DB_USERNAME', 'root');
 
-// Mysql/Postgres password
+// Database password
 define('DB_PASSWORD', '');
 
-// Mysql/Postgres hostname
+// Database hostname
 define('DB_HOSTNAME', 'localhost');
 
-// Mysql/Postgres database name
+// Database database name
 define('DB_NAME', 'kanboard');
 
-// Mysql/Postgres custom port (null = default port)
+// Database custom port (null = default port)
 define('DB_PORT', null);
 
 // Mysql SSL key
@@ -99,6 +99,9 @@ define('DB_VERIFY_SERVER_CERT', null);
 // Timeout value for PDO attribute
 define('DB_TIMEOUT', null);
 
+// ODBC DSN (default: kanboard)
+define('DB_ODBC_DSN', 'kanboard');
+
 // Enable LDAP authentication (false by default)
 define('LDAP_AUTH', false);