1 files changed, 42 insertions, 0 deletions
diff --git a/src/database/index.hpp b/src/database/index.hpp
new file mode 100644
index 0000000..5924779
--- /dev/null
+++ b/src/database/index.hpp
@@ -0,0 +1,42 @@
+#pragma once
+
+#include <sqlite3.h>
+
+#include <string>
+#include <tuple>
+
+namespace
+{
+template <std::size_t N=0, typename... T>
+typename std::enable_if<N == sizeof...(T), void>::type
+add_column_name(std::string&)
+{ }
+
+template <std::size_t N=0, typename... T>
+typename std::enable_if<N < sizeof...(T), void>::type
+add_column_name(std::string& out)
+{
+  using ColumnType = typename std::remove_reference<decltype(std::get<N>(std::declval<std::tuple<T...>>()))>::type;
+  out += ColumnType::name;
+  if (N != sizeof...(T) - 1)
+    out += ",";
+  add_column_name<N+1, T...>(out);
+}
+}
+
+template <typename... Columns>
+void create_index(sqlite3* db, const std::string& name, const std::string& table)
+{
+  std::string res{"CREATE INDEX IF NOT EXISTS "};
+  res += name + " ON " + table + "(";
+  add_column_name<0, Columns...>(res);
+  res += ")";
+
+  char* error;
+  const auto result = sqlite3_exec(db, res.data(), nullptr, nullptr, &error);
+  if (result != SQLITE_OK)
+    {
+      log_error("Error executing query: ", error);
+      sqlite3_free(error);
+    }
+}