Setup Mkdocs (#7)

* Compile docs with Mkdocs

* Add info about project

docs/dotnet/database/ado.net.md

@@ -0,0 +1,113 @@
+# [ADO.NET](https://docs.microsoft.com/en-us/dotnet/framework/data/adonet/ "ADO.NET Docs")
+
+`ADO.NET` is a set of classes that expose data access services for .NET.
+The `ADO.NET` classes are found in `System.Data.dll`, and are integrated with the XML classes found in `System.Xml.dll`.
+
+[ADO.NET provider for SQLite](https://system.data.sqlite.org/index.html/doc/trunk/www/index.wiki "System.Data.SQLite")
+
+## [Connection Strings](https://www.connectionstrings.com)
+
+### [SQL Server 2019](https://www.connectionstrings.com/sql-server-2019/)
+
+- Standard Security:
+  - `Server=<server_name>; Database=<database>; UID=<user>; Pwd=<password>;`
+  - `Server=<server_name>; Database=<database>; User ID=<user>; Password=<password>;`
+  - `Data Source=<server_name>; Initial Catalog=<database>; UID=<user>; Pwd=<password>;`
+- Specific Instance: `Server=<server_name>\<instance_name>; Database=<database>; User ID=<user>; Password=<password>;`
+- Trusted Connection (WinAuth): `Server=<server_name>; Database=<database>; Trusted_Connection=True;`
+- MARS: `Server=<server_name>; Database=<database>; Trusted_Connection=True; MultipleActiveResultSets=True;`
+
+**NOTE**: *Multiple Active Result Sets* (MARS) is a feature that works with SQL Server to allow the execution of multiple batches on a single connection.
+
+### [SQLite](https://www.connectionstrings.com/sqlite/)
+
+- Basic: `Data Source: path\to\db.sqlite3; Version=3;`
+- In-Memory Database: `Data Source=:memory:; Version=3; New=True`
+- With Password: `Data Source: path\to\db.sqlite3; Version=3; Password=<password>`
+
+## Connection to DB
+
+```cs
+using System;
+using System.Data.SqlClient;  // ADO.NET Provider, installed through NuGet
+
+namespace <namespace>
+{
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            // Connection to SQL Server DBMS
+            SqlConnectionStringBuilder connectionString = new SqlConnectionStringBuilder();
+            connectionString.DataSource = "<server_name>";
+            connectionString.UserID = "<user>";
+            connectionString.Password = "<password>";
+            connectionString.InitialCatalog = "<database>";
+
+            // more compact
+            SqlConnectionStringBuilder connectionString = new SqlConnectionStringBuilder("Server=<server_name>;Database=<database>;UID=<user>;Pwd=<password>")
+        }
+    }
+}
+```
+
+## DB Interrogation
+
+### `SqlConnection`
+
+```cs
+using (SqlConnection connection = new SqlConnection())
+{
+    connection.ConnectionString = connectionString.ConnectionString;
+    connection.Open();  // start communication w/ sql server
+}
+
+// more compact
+using (SqlConnection connection = new SqlConnection(connectionString)) {
+    connection.Open()
+}
+```
+
+### [SqlCommand](https://docs.microsoft.com/en-us/dotnet/api/system.data.sqlclient.sqlcommand)
+
+```cs
+string sql = "<sql_instruction>";
+
+using (SqlCommand command = new SqlCommand())
+{
+    command.Connection = connection;  // SqlConnection
+    command.CommandText = "... @Parameter";  // or name of StoredProcedure
+
+    // add parameters to the SqlParameterCollection, WARNING: table names or columns cannot be parameters
+    command.Parameters.Add("@Parameter", SqlDbType.<DBType>, columnLength).Value = value;
+    command.Parameters.AddWithValue("@Parameter", value);
+    command.Parameters.AddWithValue("@Parameter", (object) value ?? DBNull.Value);  // if Parameter is nullable
+
+    // Create an instance of a SqlParameter object.
+    command.CreateParameter();
+
+    command.CommandType = CommandType.Text;  // or StoredProcedure
+
+    int affectedRows = command.ExecuteNonQuery();  // execute the query and return the number of affected rows
+}
+```
+
+### `SqlDataReader`
+
+```cs
+using (SqlDataReader cursor = command.ExecuteReader())  // object to get data from db
+{
+    while (cursor.Read())  // get data till possible
+    {
+        // preferred methodology
+        cursor["<column_name>"].ToString();  // retrieve data form the column
+        cursor[<column_index>].ToString();  // retrieve data form the column
+
+        // check for null before retrieving the value
+        if(!cursor.IsDBNull(n))
+        {
+            cursor.Get<SystemType>(index);  // retrieve data form the n-th column
+        }
+    }
+}
+```