From 393eeb8649a2e2752012e3ea7b4d287a53eea74f Mon Sep 17 00:00:00 2001
From: Alexander Plavin <alexander@plav.in>
Date: Fri, 30 Aug 2024 11:07:49 -0400
Subject: [PATCH] support duckdb

---
 src/dialects.jl |  9 ++++++++-
 src/reflect.jl  | 14 ++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/src/dialects.jl b/src/dialects.jl
index 6bc22ac5..d39915db 100644
--- a/src/dialects.jl
+++ b/src/dialects.jl
@@ -151,6 +151,11 @@ const postgresql_dialect =
                limit_style = LIMIT_STYLE.POSTGRESQL,
                variable_prefix = '$',
                variable_style = VARIABLE_STYLE.NUMBERED)
+const duckdb_dialect =
+    SQLDialect(name = :duckdb,
+               limit_style = LIMIT_STYLE.POSTGRESQL,
+               variable_prefix = '$',
+               variable_style = VARIABLE_STYLE.NUMBERED)
 const redshift_dialect =
     SQLDialect(name = :redshift,
                concat_operator = Symbol("||"),
@@ -187,7 +192,8 @@ const standard_dialects = [
     spark_dialect,
     sqlite_dialect,
     sqlserver_dialect,
-    default_dialect]
+    default_dialect,
+    duckdb_dialect]
 
 function SQLDialect(name::Symbol; kws...)
     for sd in standard_dialects
@@ -210,6 +216,7 @@ const known_connection_types = [
     [:MySQL, :Connection] => :mysql,
     [:LibPQ, :Connection] => :postgresql,
     [:SQLite, :DB] => :sqlite,
+    [:DuckDB, :DB] => :duckdb,
 ]
 
 function SQLDialect(@nospecialize ConnType::Type)
diff --git a/src/reflect.jl b/src/reflect.jl
index 417fe69e..900dc3de 100644
--- a/src/reflect.jl
+++ b/src/reflect.jl
@@ -26,6 +26,19 @@ const postgresql_reflect_clause =
     SELECT(:schema => (:n, :nspname),
            :name => (:c, :relname),
            :column => (:a, :attname))
+# same as postgresql, just the default schema is "main" instead of "public":
+const duckdb_reflect_clause =
+    FROM(:n => (:pg_catalog, :pg_namespace)) |>
+    JOIN(:c => (:pg_catalog, :pg_class), on = FUN("=", (:n, :oid), (:c, :relnamespace))) |>
+    JOIN(:a => (:pg_catalog, :pg_attribute), on = FUN("=", (:c, :oid), (:a, :attrelid))) |>
+    WHERE(FUN(:and, FUN("=", (:n, :nspname), FUN(:coalesce, VAR(:schema), "main")),
+                    FUN(:in, (:c, :relkind), "r", "v"),
+                    FUN(">", (:a, :attnum), 0),
+                    FUN(:not, (:a, :attisdropped)))) |>
+    ORDER((:n, :nspname), (:c, :relname), (:a, :attnum)) |>
+    SELECT(:schema => (:n, :nspname),
+        :name => (:c, :relname),
+        :column => (:a, :attname))
 const redshift_reflect_clause = postgresql_reflect_clause
 const sqlite_reflect_clause =
     FROM(:sm => :sqlite_master) |>
@@ -49,6 +62,7 @@ const sqlserver_reflect_clause =
 const standard_reflect_clauses = [
     :mysql => mysql_reflect_clause,
     :postgresql => postgresql_reflect_clause,
+    :duckdb => duckdb_reflect_clause,
     :redshift => redshift_reflect_clause,
     :sqlite => sqlite_reflect_clause,
     :sqlserver => sqlserver_reflect_clause]