vennim / data

Lightweight DB-independent schema-less DAL for .NET Core: abstract queries, SQL commands builder, POCO mapping.

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 14.04

• 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, can be constructed dynamically
• generate several SQL statements into one IDbCommand (batch inserts, updates, selects for multiple recordsets: DbBatchCommandBuilder)
• supports annotated POCO models (EF Core entity models), custom query result mapping
• API for schema-less data access (dictionaries / RecordSet)
• can handle results returned by stored procedure, 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 etc)
• supports both full .NET Framework 4.5+ and .NET Core (netstandard1.5)

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 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 and maps it to models, dictionaries 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 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
• 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)

License

Copyright 2016-2017 Vitaliy Fedorchenko and contributors

Distributed under the MIT license