Nullable params

Author: OlegGalizin

clickhouse/base/wire_format.cpp

@@ -113,7 +113,14 @@ inline const char* find_quoted_chars(const char* start, const char* end) {
     return nullptr;
 }
 
-void WireFormat::WriteQuotedString(OutputStream& output, std::string_view value) {
+void WireFormat::WriteQuotedString(OutputStream& output, std::optional<std::string_view> opt) {
+    if (!opt) //NULL
+    {
+        WriteVarint64(output, 5);
+        WriteAll(output, "'\\\\N'", 5);
+        return;
+    }
+    std::string_view value = *opt;
     auto size               = value.size();
     const char* start       = value.data();
     const char* end         = start + size;

clickhouse/base/wire_format.h

@@ -2,6 +2,7 @@
 
 #include <string>
 #include <cstdint>
+#include <optional>
 
 namespace clickhouse {
 
@@ -22,7 +23,7 @@ class WireFormat {
     static void WriteFixed(OutputStream& output, const T& value);
     static void WriteBytes(OutputStream& output, const void* buf, size_t len);
     static void WriteString(OutputStream& output, std::string_view value);
-    static void WriteQuotedString(OutputStream& output, std::string_view value);
+    static void WriteQuotedString(OutputStream& output, std::optional<std::string_view> value);
     static void WriteUInt64(OutputStream& output, const uint64_t value);
     static void WriteVarint64(OutputStream& output, uint64_t value);
 

clickhouse/query.h

@@ -26,7 +26,8 @@ struct QuerySettingsField {
 };
 
 using QuerySettings = std::unordered_map<std::string, QuerySettingsField>;
-using QueryParams = std::unordered_map<std::string, std::string>;
+using QueryParamValue = std::optional<std::string>;
+using QueryParams = std::unordered_map<std::string, QueryParamValue>;
 
 struct Profile {
     uint64_t rows = 0;
@@ -123,7 +124,7 @@ class Query : public QueryEvents {
         return *this;
     }
 
-    inline Query& SetParam(const std::string& name, const std::string& value) {
+    inline Query& SetParam(const std::string& name, const QueryParamValue& value) {
         query_params_[name] = value;
         return *this;
     }

tests/simple/main.cpp

@@ -278,6 +278,33 @@ inline void ParamExample(Client& client) {
     client.Execute("DROP TEMPORARY TABLE test_client");
 }
 
+inline void ParamNullExample(Client& client) {
+    client.Execute("CREATE TEMPORARY TABLE IF NOT EXISTS test_client (id UInt64, name Nullable(String))");
+
+    Query query("insert into test_client values ({id: UInt64}, {name: Nullable(String)})");
+
+    query.SetParam("id", "123").SetParam("name", QueryParamValue());
+    client.Execute(query);
+
+    query.SetParam("id", "456").SetParam("name", "String Value");
+    client.Execute(query);
+
+    client.Select("SELECT id, name FROM test_client", [](const Block& block) {
+        for (size_t c = 0; c < block.GetRowCount(); ++c) {
+            std::cerr << block[0]->As<ColumnUInt64>()->At(c) << " ";
+
+            auto col_string = block[1]->As<ColumnNullable>();
+            if (col_string->IsNull(c)) {
+                std::cerr << "\\N\n";
+            } else {
+                std::cerr << col_string->Nested()->As<ColumnString>()->At(c) << "\n";
+            }
+        }
+    });
+
+    client.Execute("DROP TEMPORARY TABLE test_client");
+}
+
 inline void NullableExample(Client& client) {
     /// Create a table.
     client.Execute("CREATE TEMPORARY TABLE IF NOT EXISTS test_client (id Nullable(UInt64), date Nullable(Date))");
@@ -523,6 +550,7 @@ inline void IPExample(Client &client) {
 
 static void RunTests(Client& client) {
     ParamExample(client);
+    ParamNullExample(client);
     ArrayExample(client);
     CancelableExample(client);
     DateExample(client);