Rename to QueryScalars for #812

Author: praeclarum

src/SQLite.cs

@@ -970,11 +970,27 @@ public T ExecuteScalar<T> (string query, params object[] args)
 			var cmd = CreateCommand (query, args);
 			return cmd.ExecuteQuery<T> ();
 		}
-		public List<T> SingleQuery<T> (string query, params object[] args)
+
+		/// <summary>
+		/// Creates a SQLiteCommand given the command text (SQL) with arguments. Place a '?'
+		/// in the command text for each of the arguments and then executes that command.
+		/// It returns the first column of each row of the result.
+		/// </summary>
+		/// <param name="query">
+		/// The fully escaped SQL.
+		/// </param>
+		/// <param name="args">
+		/// Arguments to substitute for the occurences of '?' in the query.
+		/// </param>
+		/// <returns>
+		/// An enumerable with one result for the first column of each row returned by the query.
+		/// </returns>
+		public List<T> QueryScalars<T> (string query, params object[] args)
 		{
 			var cmd = CreateCommand (query, args);
-			return cmd.ExcuteSingleQuery<T> ().ToList ();
+			return cmd.ExecuteQueryScalars<T> ().ToList ();
 		}
+
 		/// <summary>
 		/// Creates a SQLiteCommand given the command text (SQL) with arguments. Place a '?'
 		/// in the command text for each of the arguments and then executes that command.
@@ -2849,31 +2865,6 @@ protected virtual void OnInstanceCreated (object obj)
 		{
 			// Can be overridden.
 		}
-		public IEnumerable<T> ExcuteSingleQuery<T> ()
-		{
-			if (_conn.Trace) {
-				_conn.Tracer?.Invoke ("Executing Query: " + this);
-			}
-			var stmt = Prepare ();
-			try {
-				if (SQLite3.ColumnCount (stmt) != 1) {
-					throw new NotSupportedException ("Column count error");
-				}
-				while (SQLite3.Step (stmt) == SQLite3.Result.Row) {
-					var colType = SQLite3.ColumnType (stmt, 0);
-					var val = ReadCol (stmt, 0, colType, typeof (T));
-					if (val == null) {
-						yield return default (T);
-					}
-					else {
-						yield return (T)val;
-					}
-				}
-			}
-			finally {
-				Finalize (stmt);
-			}
-		}
 
 		public IEnumerable<T> ExecuteDeferredQuery<T> (TableMapping map)
 		{
@@ -2940,6 +2931,32 @@ public T ExecuteScalar<T> ()
 			return val;
 		}
 
+		public IEnumerable<T> ExecuteQueryScalars<T> ()
+		{
+			if (_conn.Trace) {
+				_conn.Tracer?.Invoke ("Executing Query: " + this);
+			}
+			var stmt = Prepare ();
+			try {
+				if (SQLite3.ColumnCount (stmt) < 1) {
+					throw new InvalidOperationException ("QueryScalars should return at least one column");
+				}
+				while (SQLite3.Step (stmt) == SQLite3.Result.Row) {
+					var colType = SQLite3.ColumnType (stmt, 0);
+					var val = ReadCol (stmt, 0, colType, typeof (T));
+					if (val == null) {
+						yield return default (T);
+					}
+					else {
+						yield return (T)val;
+					}
+				}
+			}
+			finally {
+				Finalize (stmt);
+			}
+		}
+
 		public void Bind (string name, object val)
 		{
 			_bindings.Add (new Binding {

src/SQLiteAsync.cs

@@ -1070,17 +1070,18 @@ public Task<T> ExecuteScalarAsync<T> (string query, params object[] args)
 		/// Arguments to substitute for the occurences of '?' in the query.
 		/// </param>
 		/// <returns>
-		/// An enumerable with one result for each row returned by the query.
+		/// A list with one result for each row returned by the query.
 		/// </returns>
 		public Task<List<T>> QueryAsync<T> (string query, params object[] args)
 			where T : new()
 		{
 			return ReadAsync (conn => conn.Query<T> (query, args));
 		}
+
 		/// <summary>
 		/// Creates a SQLiteCommand given the command text (SQL) with arguments. Place a '?'
 		/// in the command text for each of the arguments and then executes that command.
-		/// It returns single row of the result 
+		/// It returns the first column of each row of the result.
 		/// </summary>
 		/// <param name="query">
 		/// The fully escaped SQL.
@@ -1089,12 +1090,13 @@ public Task<List<T>> QueryAsync<T> (string query, params object[] args)
 		/// Arguments to substitute for the occurences of '?' in the query.
 		/// </param>
 		/// <returns>
-		/// An enumerable with one result for single row returned by the query.
+		/// A list with one result for the first column of each row returned by the query.
 		/// </returns>
-		public Task<List<T>> SingleQueryAsync<T> (string query, params object[] args)
+		public Task<List<T>> QueryScalarsAsync<T> (string query, params object[] args)
 		{
-			return ReadAsync (conn => conn.SingleQuery<T> (query, args));
+			return ReadAsync (conn => conn.QueryScalars<T> (query, args));
 		}
+
 		/// <summary>
 		/// Creates a SQLiteCommand given the command text (SQL) with arguments. Place a '?'
 		/// in the command text for each of the arguments and then executes that command.

tests/AsyncTests.cs

@@ -474,7 +474,7 @@ public void TestSingleQueryAsync ()
 			}
 
 			// return the third one...
-			var task = conn.SingleQueryAsync<string> ("select Email from customer where id=?", customers[2].Id);
+			var task = conn.QueryScalarsAsync<string> ("select Email from customer where id=?", customers[2].Id);
 			task.Wait ();
 			var loaded = task.Result;
 
@@ -483,7 +483,7 @@ public void TestSingleQueryAsync ()
 			Assert.AreEqual (customers[2].Email, loaded[0]);
 
 			// return the third one...
-			var inttest = conn.SingleQueryAsync<int> ("select Id from customer where id=?", customers[2].Id);
+			var inttest = conn.QueryScalarsAsync<int> ("select Id from customer where id=?", customers[2].Id);
 			task.Wait ();
 			var intloaded = inttest.Result;
 
@@ -492,7 +492,7 @@ public void TestSingleQueryAsync ()
 			Assert.AreEqual (customers[2].Id, intloaded[0]);
 
 			// return string list
-			var listtask = conn.SingleQueryAsync<string> ("select Email from customer order by Id");
+			var listtask = conn.QueryScalarsAsync<string> ("select Email from customer order by Id");
 			listtask.Wait ();
 			var listloaded = listtask.Result;
 
@@ -501,8 +501,8 @@ public void TestSingleQueryAsync ()
 			Assert.AreEqual (customers[2].Email, listloaded[2]);
 
 			// select columns
-			var columnstask= conn.SingleQueryAsync<string> ("select * from customer");
-			ExceptionAssert.Throws<AggregateException> (() => columnstask.Wait ());
+			var columnstask= conn.QueryScalarsAsync<string> ("select FirstName, LastName from customer");
+			Assert.AreEqual (5, columnstask.Result.Count);
 		}
 		[Test]
 		public void TestTableAsync ()