Awesome

NReco.Data

Lightweight high-performance data access components for generating SQL commands, mapping results to strongly typed POCO models or dictionaries, schema-less CRUD-operations with RecordSet.

NuGet	Windows x64	Ubuntu

very fast: NReco.Data shows almost the same performance as Dapper but offers more features
abstract DB-independent Query structure: no need to compose raw SQL in the code + query can be constructed dynamically (at run-time)
automated CRUD commands generation
generate several SQL statements into one IDbCommand (batch inserts, updates, selects for multiple recordsets: DbBatchCommandBuilder)
supports mapping to annotated POCO models (EF Core entity models), allows customized mapping of query result
API for schema-less data access (dictionaries, RecordSet, DataTable)
can handle results returned by stored procedure, including multiple record sets
application-level data views (for complex SQL queries) that accessed like simple read-only tables (DbDataView)
parser for compact string query representation: relex expressions
can be used with any existing ADO.NET data provider (SQL Server, PostgreSql, Sqlite, MySql, Oracle etc)
supports .NET Framework 4.5+, .NET Core 2.x / 3.x (netstandard2.0)

Quick reference

Class	Dependencies	Purpose
`DbFactory`		incapsulates DB-specific functions and conventions
`DbCommandBuilder`	IDbFactory	composes IDbCommand and SQL text for SELECT/UPDATE/DELETE/INSERT, handles app-level dataviews
`DbDataAdapter`	IDbCommandBuilder, IDbConnection	CRUD operations for model, dictionary, DataTable or RecordSet: Insert/Update/Delete/Select. Async versions are supported for all methods.
`Query`		Represents abstract query to database; used as parameter in DbCommandBuilder, DbDataAdapter
`RelexParser`		Parsers query string expression (Relex) into Query structure
`RecordSet`		RecordSet model represents in-memory data records, this is lightweight and efficient replacement for classic DataTable/DataRow
`DataReaderResult`	IDataReader	reads data from any data reader implementation and efficiently maps it to models, dictionaries, DataTable or RecordSet

NReco.Data documentation:

Getting started and HowTos
Full API Reference
something is still not clear? Feel free to ask a question on StackOverflow

How to use

Generic implementation of DbFactory can be used with any ADO.NET connector.

DbFactory initialization for SqlClient:

var dbFactory = new DbFactory(System.Data.SqlClient.SqlClientFactory.Instance) {
	LastInsertIdSelectText = "SELECT @@IDENTITY" };

DbFactory initialization for Mysql:

var dbFactory = new DbFactory(MySql.Data.MySqlClient.MySqlClientFactory.Instance) {
	LastInsertIdSelectText = "SELECT LAST_INSERT_ID()" };

DbFactory initialization for Postgresql:

var dbFactory = new DbFactory(Npgsql.NpgsqlFactory.Instance) {
	LastInsertIdSelectText = "SELECT lastval()" };

DbFactory initialization for Sqlite:

var dbFactory = new DbFactory(Microsoft.Data.Sqlite.SqliteFactory.Instance) {
	LastInsertIdSelectText = "SELECT last_insert_rowid()" };

DbCommandBuilder generates SQL commands by Query:

var dbCmdBuilder = new DbCommandBuilder(dbFactory);
var selectCmd = dbCmdBuilder.GetSelectCommand( 
	new Query("Employees", (QField)"BirthDate" > new QConst(new DateTime(1960,1,1)) ) );
var selectGroupByCmd = dbCmdBuilder.GetSelectCommand( 
	new Query("Employees").Select("company_id", new QAggregateField("avg_age", "AVG", "age") ) );
var insertCmd = dbCmdBuilder.GetInsertCommand(
	"Employees", new { Name = "John Smith", BirthDate = new DateTime(1980,1,1) } );
var deleteCmd = dbCmdBuilder.GetDeleteCommand(
	new Query("Employees", (QField)"Name" == (QConst)"John Smith" ) );

DbDataAdapter - provides simple API for CRUD-operations:

var dbConnection = dbFactory.CreateConnection();
dbConnection.ConnectionString = "<db_connection_string>";
var dbAdapter = new DbDataAdapter(dbConnection, dbCmdBuilder);
// map select results to POCO models
var employeeModelsList = dbAdapter.Select( new Query("Employees") ).ToList<Employee>();
// read select result to dictionary
var employeeDictionary = dbAdapter.Select( 
    new Query("Employees", (QField)"EmployeeID"==(QConst)newEmployee.EmployeeID ).Select("FirstName","LastName") 
  ).ToDictionary();
// update by dictionary
dbAdapter.Update( 
	new Query("Employees", (QField)"EmployeeID"==(QConst)1001 ),
	new Dictionary<string,object>() {
		{"FirstName", "Bruce" },
		{"LastName", "Wayne" }
	});
// insert by model
dbAdapter.Insert( "Employees", new { FirstName = "John", LastName = "Smith" } );

RecordSet - efficient replacement for DataTable/DataRow with very similar API:

var rs = dbAdapter.Select(new Query("Employees")).ToRecordSet();
rs.SetPrimaryKey("EmployeeID");
foreach (var row in rs) {
	Console.WriteLine("ID={0}", row["EmployeeID"]);
	if ("Canada".Equals(row["Country"]))
		row.Delete();
}
dbAdapter.Update(rs);
var rsReader = new RecordSetReader(rs); // DbDataReader for in-memory rows

Relex - compact relational query expressions:

var relex = @"Employees(BirthDate>""1960-01-01"":datetime)[Name,BirthDate]"
var relexParser = new NReco.Data.Relex.RelexParser();
Query q = relexParser.Parse(relex);

More examples

Command Builder: illustrates SQL commands generation, command batching (inserts)
Data Adapter: CRUD operations with dictionaries, POCO, RecordSet
DataSet GenericDataAdapter: how to implement generic DataSet DataAdapter (Fill/Update) for any ADO.NET provider
SQL logging: how to extend DbFactory and add wrapper for DbCommand that logs SQL commands produced by DbDataAdapter
DB WebApi: configures NReco.Data services in MVC Core app, simple REST API for database tables
MVC Core CRUD: full-functional CRUD (list, add/edit forms) that uses NReco.Data as data layer in combination with EF Core
DB Metadata: extract database metadata (list of tables, columns) with information_schema queries
GraphQL API for SQL database: provides simple GraphQL API by existing database schema (simple queries only, no mutations yet)

Who is using this?

NReco.Data is in production use at SeekTable.com and PivotData microservice.

License

Distributed under the MIT license