ClickHouse/src/TableFunctions/TableFunctionGenerateRandom.h
2023-01-12 22:29:23 +00:00

37 lines
1.3 KiB
C++

#pragma once
#include <TableFunctions/ITableFunction.h>
namespace DB
{
/* generateRandom([structure, max_array_length, max_string_length, random_seed])
* - creates a temporary storage that generates columns with random data
*/
class TableFunctionGenerateRandom : public ITableFunction
{
public:
static constexpr auto name = "generateRandom";
std::string getName() const override { return name; }
bool hasStaticStructure() const override { return structure != "auto"; }
bool needStructureHint() const override { return structure == "auto"; }
void setStructureHint(const ColumnsDescription & structure_hint_) override { structure_hint = structure_hint_; }
private:
StoragePtr executeImpl(const ASTPtr & ast_function, ContextPtr context, const std::string & table_name, ColumnsDescription cached_columns) const override;
const char * getStorageTypeName() const override { return "GenerateRandom"; }
ColumnsDescription getActualTableStructure(ContextPtr context) const override;
void parseArguments(const ASTPtr & ast_function, ContextPtr context) override;
String structure = "auto";
UInt64 max_string_length = 10;
UInt64 max_array_length = 10;
std::optional<UInt64> random_seed;
ColumnsDescription structure_hint;
};
}