DataCore - Micro ORM for C

DataCore’s goal is to be a FOSS alternative to other ORMs. Focusing on simplicity and developer control over the queries and the database.

It uses Dapper for SQL execution and creates a layer on top of it to ease the query creation and database maintenance.

Download

For now there’s no Nuget version, so you have to download/clone and build the current version from GitHub.

Supported Databases

• SQLite
• SQL Server
• Oracle DB
• Postgres
• MariaDB (through MySQL, full support)
• MySQL (partial - no index support - planned for full release)

Each database has its own project. You can only add what you’ll use.

Usage

Each class represents one table and one table only.

Create a database for a connection using the desired provider and then you can use all methods from it.

Small Example

class User
{
  public int Id { get; set; }
  public string Name { get; set; }
}
using (var db = new DataCoreDatabase(new SqliteDatabase(), "Data Source=:memory:"))
{
    db.CreateTable<User>();
    db.Insert(new User { Id = 1, Name = "Test User" });
    var user = db.Select<User>(u => u.Id == 1);
}

Simple Selects

Select with Where

db.Select<User>(u => u.Id == 1);

Select one record with Where

db.SelectSingle<User>(u => u.Id == 1);

Select By Id

db.SelectById<User>(1);

Select By Ids

db.SelectById<User>(1, 2, 3);

Query object

You can use the Query class to create more complex queries.

var query = db.From<User>(); // creates query object
// create query using object
var result = db.Select(query); // executes the query
var result = db.Select<MaxUser>(query); // returning other class (when changing field names)

Joins

var query = db.From<User>().Join<Address>((u, a) => u.Id == a.UserId);
var result = db.Select(query);

var query = db.From<User>()
              .LeftJoin<Address>((u, a) => u.Id == a.UserId)
              .Where<Address>(a => a.Street.Like("Avenue%"));
var result = db.Select(query);

// note: not supported by SQLite
var query = db.From<User>().RightJoin<Address>((u, a) => u.Id == a.UserId);
var result = db.Select(query);

Group By

var query = db.From<User>().GroupBy(u => u.Name).Count();
var result = db.Select(query);

var query = db.From<User>().GroupBy(u => new { u.Name, u.Age }).Count();
var result = db.Select(query);

var query = db.From<User>().GroupBy(u => u.Name).Having(u => u.Age.Sum() > 100).Count();
var result = db.Select(query);

var query = db.From<User>()
              .LeftJoin<Address>((u, a) => u.Id == a.UserId)
              .GroupBy(u => u.Name)
              .GroupBy<Address>(a => a.Street)
              .Having(u => u.Age.Sum() > 100)
              .Having<Address>(a => a.Sum.Number.Count() > 2)
              .Count();
var result = db.Select(query);

Select Columns

var query = db.From<User>().Select(u => u.Id);
var result = db.Select(query);

var query = db.From<User>().Select(u => new { u.Id, u.Name });
var result = db.Select(query);

var query = db.From<User>().Select(u => new { u.Id, u.Name.Lower().As("Name") });
var result = db.Select(query);

var query = db.From<User>().Join<Address>((u, a) => u.Id == a.UserId)
              .Select(u => u.Id).Select<Address>(a => a.Street);
var result = db.Select(query);

Select Exists

var query = database.From<User>().Where(u => u.Id == 1);
bool exists = database.Exists(query);

bool exists = database.Exists<User>(u => u.Id == 1);

Extensions

You can use these extensions to use some SQL methods on your queries.

var query = db.From<User>().Select(u => u.Id.TrimSql());
var result = db.Select(query);

var result = db.Select<User>(u => u.Name.Like("%Test%"));

var query = db.From<User>().GroupBy(u => u.Age.IsNull(0)).Select(u => new { u.Age, u.Name.Length().Min().As("MinName") });
var result = db.Select(query);

All available extensions

Sum()
Min()
Max()
Average()
Count()
Between(start, end)
In(value1, value2, ...)
Like(string)
TrimSql()
Length()
Upper()
Lower()
IsNull(otherValue)
Cast<To>()
As(alias)

Record Maintenance

Insert

db.Insert<User>(new User { Id = 1, Name = "Test User" });

Update

// updates user with Id = 1 with user data
db.Update<User>(user, u => u.Id == 1);

Update Only

// only updates the name of the User with Id = 1
db.UpdateOnly<User>(user, t => t.Name, u => u.Id == 1);

Delete

// delete user with Id = 1
db.Delete<User>(u => u.Id == 1);

Delete By Id

// delete user with Id = 1
db.DeleteById<User>(1);

Delete By Ids

// delete user with Ids 1, 2 and 3
db.DeleteById<User>(1, 2, 3);

Database Schemas

You can use the following methods to create and drop parts of your database:

// databases (does not work for OracleDB)
db.CreateDatabase("test_db");
db.CreateDatabaseIfNotExists("test_db");
db.DatabaseExists("test_db"); // returns true
db.DropDatabaseIfExists("test_db");
db.DropDatabase("test_db");
// tables
db.CreateTable<User>();
db.CreateTables(typeof(User), typeof(Address));
db.CreateTableIfNotExists<User>();
db.CreateTablesIfNotExists(typeof(User), typeof(Address));
db.TableExists<User>(); // returns true
db.DropTable<User>();
db.DropTables(typeof(User), typeof(Address));
db.DropTableIfExists<User>();
db.DropTablesIfExists(typeof(User), typeof(Address));
db.DropAndCreateTable<User>();
db.DropAndCreateTables(typeof(User), typeof(Address));
// columns
db.CreateColumn<User>(t => t.NewColumn);
db.CreateColumnIfNotExists<User>(t => t.NewColumn);
db.ColumnExists<User>("NewColumn"); // returns true
db.ColumnExists<User>(t => t.NewColumn); // returns true
db.DropColumn<User>(t => t.NewColumn);
db.DropColumnIfExists<User>(t => t.NewColumn);
// indexes
db.CreateIndex<User>(t => new { t.Id, t.Name }, true, "IX_User_IdName_Unique");
db.CreateIndexIfNotExists<User>(t => new { t.Id, t.Name }, true, "IX_User_IdName_Unique");
db.IndexExists<User>("IX_User_IdName_Unique"); // returns true
db.IndexExists<User>(t => new { t.Id, t.Name }); // returns true
db.DropIndex<User>("IX_User_IdName_Unique");
db.DropIndexIfExists<User>("IX_User_IdName_Unique");
// foreign keys
db.CreateForeignKey<User, Address>(u => u.Id, a => a.UserId, "FK_User_Address");
db.CreateForeignKeyIfNotExists<User, Address>(u => u.Id, a => a.UserId, "FK_User_Address");
db.ForeignKeyExists<User>("FK_User_Address"); // returns true
db.ForeignKeyExists<User, Address>(u => u.Id, a => a.UserId); // returns true
db.DropForeignKey<User>("FK_User_Address");
db.DropForeignKeyIfExists<User>("FK_User_Address");

For automatic generation and Id usage, the following attributes can be used to decorate your properties.

[Table("USER")] // explicit table name
class User
{
  // set as primary key, with the column name, and with AutoIncrement
  [Column(isPrimaryKey: true, columnName: "User_ID"), Identity]
  public int Id { get; set; }
  // create an index when creating the table
  [Index]
  public string Login { get; set; }
  public string Name { get; set; }
  // set as nullable
  [Column(isRequired: false)]
  public DateTime InsertDate { get; set; }
  // ignore the field for db
  [Ignore]
  public float Number { get; set; }
  // create a foreign key to Address with the name provided
  [Reference(typeof(Address), "FK_User_Address")]
  public int AddressId { get; set; }
}

Contributing

All push requests are welcome.

Notes

Aditional usages can be found in the test project.