Improve support for declarative partitioning.

Generated SQL for a partition is now correct (atleast for simple cases)
Switched to C++ 20 so the ranges library can be used in this case
to filter unwanted items.

pglablib/catalog/PgClass.cpp

@@ -6,7 +6,7 @@
 #include "PgInheritsContainer.h"
 #include <QStringBuilder>
 #include "SqlFormattingUtils.h"
-
+#include <ranges>
 
 
 void operator<<(RelPersistence &s, const Pgsql::Value &v)
@@ -125,52 +125,90 @@ QString PgClass::createTableSql() const
 		sql += "TEMP ";
 	sql += "TABLE ";
 	sql += fullyQualifiedQuotedObjectName();
-	sql += " (\n    ";
 
-	auto && cols = catalog().attributes()->getColumnsForRelation(oid());
-	bool first = true;
-    for (auto && col : cols)
+    if (!partitionBoundaries.isEmpty())
     {
-        if (col.num > 0 && !col.isdropped)
-        {
-            if (first)
-            {
-				first = false;
-			}
-            else
-                sql += ",\n    ";
-			if (!col.islocal) sql += "-- ";
-			sql += col.columnDefinition(catalog());
-		}
-//			  { column_name data_type [ COLLATE collation ] [ column_constraint [ ... ] ]
-//				| table_constraint
-//			] )
-	}
-	auto && constraints = catalog().constraints()->getConstraintsForRelation(oid());
-    for (auto && constraint: constraints)
-    {
-        if (first)
-        {
-			sql += "\n    ";
-			first = false;
-		}
-        else
-            sql += ",\n    ";
-		sql += getConstraintDefinition(catalog(), constraint, "      ");
-	}
+        sql += " PARTITION OF " + getPartitionOfName();
+        sql += generateBodySql(true);
+    }
+    else
+        sql += generateBodySql(false);
 
-    sql += "\n)"
-        % generateInheritsSql()
-            //			[ PARTITION BY { RANGE | LIST } ( { column_name | ( expression ) } [ COLLATE collation ] [ opclass ] [, ... ] ) ]
-            //			[ WITH ( storage_parameter [= value] [, ... ] ) | WITH OIDS | WITHOUT OIDS ]
-            //			[ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
+    sql += generateInheritsSql()
         % generateTablespaceSql()
         % ";\n";
     return sql;
 }
 
+QString PgClass::generateBodySql(bool isPartition) const
+{
+    // - also remove commented inherited column list? They are listed in the column view no need for them in sql
+    // - mark them in the view as inherited?
+    // - detect when body empty and leave it out completely (only for partitions, is leaving it out always legal?)
+    // - need to detect "inherited" constraint because these should not be listed either
+
+
+    auto colsFilter = isPartition ?
+            [] (const PgAttribute &c)
+                    {
+                        return c.num > 0 // ignore system columns
+                            && !c.isdropped // ignore dropped columns
+                            && c.islocal;
+                    }
+            :
+            [] (const PgAttribute &c)
+                    {
+                        return c.num > 0 // ignore system columns
+                            && !c.isdropped; // ignore dropped columns
+                    }
+            ;
+
+    auto && cols = catalog().attributes()->getColumnsForRelation(oid())
+        | std::views::filter(colsFilter);
+    auto && constraints = catalog().constraints()->getConstraintsForRelation(oid())
+        | std::views::filter([] (const auto &c) { return c.islocal; });
+
+    if (cols.empty() && constraints.empty())
+        return {};
+
+    QString sql = " (\n    ";
+
+    bool first = true;
+    for (auto && col : cols)
+    {
+        if (first)
+        {
+            first = false;
+        }
+        else
+            sql += ",\n    ";
+        if (!col.islocal) sql += "-- ";
+        sql += col.columnDefinition(catalog());
+    }
+
+
+    for (auto && constraint: constraints)
+    {
+        if (first)
+        {
+            sql += "\n    ";
+            first = false;
+        }
+        else
+            sql += ",\n    ";
+        sql += getConstraintDefinition(catalog(), constraint, "      ");
+    }
+
+    sql += "\n)";
+
+    return sql;
+}
+
 QString PgClass::generateInheritsSql() const
 {
+    if (!partitionBoundaries.isEmpty())
+        return "\n" + partitionBoundaries;
+
     QString sql;
     //			[ INHERITS ( parent_table [, ... ] ) ]
     auto parents = catalog().inherits()->getParentsOf(oid());
@@ -189,6 +227,16 @@ QString PgClass::generateInheritsSql() const
     return sql;
 }
 
+QString PgClass::getPartitionOfName() const
+{
+    auto parents = catalog().inherits()->getParentsOf(oid());
+    if (!parents.empty())
+    {
+        return catalog().classes()->getByKey(parents.front())->fullyQualifiedQuotedObjectName();
+    }
+    throw std::logic_error("Should only be called if there is a parent table");
+}
+
 QString PgClass::generateTablespaceSql() const
 {
     if (tablespace != 0)

pglablib/catalog/PgClass.h

@@ -62,7 +62,9 @@ private:
 	mutable QString createSqlCache;
 
 	QString createTableSql() const;
+    QString generateBodySql(bool isPartition) const;
     QString generateInheritsSql() const;
+    QString getPartitionOfName() const;
     QString generateTablespaceSql() const;
 	QString createViewSql() const;
 };

pglablib/catalog/PgConstraint.h

@@ -79,6 +79,10 @@ public:
 
 	QString dropSql() const override;
 	QString createSql() const override;
+    bool isInherited() const
+    {
+        return inhcount > 0;
+    }
 };