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#include <Common/Exception.h>
#include <Storages/StorageGenerateRandom.h>
#include <Storages/checkAndGetLiteralArgument.h>
#include <Parsers/ASTExpressionList.h>
#include <Parsers/ASTLiteral.h>
#include <TableFunctions/ITableFunction.h>
#include <TableFunctions/TableFunctionFactory.h>
#include <TableFunctions/TableFunctionGenerateRandom.h>
#include <Functions/FunctionGenerateRandomStructure.h>
#include <Interpreters/parseColumnsListForTableFunction.h>
#include <Interpreters/evaluateConstantExpression.h>
#include <Common/randomSeed.h>
#include "registerTableFunctions.h"
namespace DB
{
namespace ErrorCodes
{
extern const int BAD_ARGUMENTS;
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
extern const int LOGICAL_ERROR;
}
void TableFunctionGenerateRandom::parseArguments(const ASTPtr & ast_function, ContextPtr context)
{
ASTs & args_func = ast_function->children;
if (args_func.size() != 1)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Table function '{}' must have arguments.", getName());
ASTs & args = args_func.at(0)->children;
if (args.empty())
return;
/// First, check if first argument is structure or seed.
const auto * first_arg_literal = args[0]->as<const ASTLiteral>();
bool first_argument_is_structure = !first_arg_literal || first_arg_literal->value.getType() == Field::Types::String;
size_t max_args = first_argument_is_structure ? 4 : 3;
if (args.size() > max_args)
throw Exception(ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH,
"Table function '{}' requires at most four (or three if structure is missing) arguments: "
" [structure, random_seed, max_string_length, max_array_length].", getName());
if (first_argument_is_structure)
{
/// Allow constant expression for structure argument, it can be generated using generateRandomStructure function.
args[0] = evaluateConstantExpressionAsLiteral(args[0], context);
}
// All the arguments must be literals.
for (const auto & arg : args)
{
if (!arg->as<const ASTLiteral>())
{
throw Exception(ErrorCodes::BAD_ARGUMENTS,
"All arguments of table function '{}' except structure argument must be literals. "
"Got '{}' instead", getName(), arg->formatForErrorMessage());
}
}
size_t arg_index = 0;
if (first_argument_is_structure)
{
/// Parsing first argument as table structure and creating a sample block
structure = checkAndGetLiteralArgument<String>(args[arg_index], "structure");
++arg_index;
}
if (args.size() >= arg_index + 1)
{
const auto & literal = args[arg_index]->as<const ASTLiteral &>();
++arg_index;
if (!literal.value.isNull())
random_seed = checkAndGetLiteralArgument<UInt64>(literal, "random_seed");
}
if (args.size() >= arg_index + 1)
{
max_string_length = checkAndGetLiteralArgument<UInt64>(args[arg_index], "max_string_length");
++arg_index;
}
if (args.size() == arg_index + 1)
{
max_array_length = checkAndGetLiteralArgument<UInt64>(args[arg_index], "max_string_length");
++arg_index;
}
}
ColumnsDescription TableFunctionGenerateRandom::getActualTableStructure(ContextPtr context, bool /*is_insert_query*/) const
{
if (structure == "auto")
{
if (structure_hint.empty())
{
auto random_structure = FunctionGenerateRandomStructure::generateRandomStructure(random_seed.value_or(randomSeed()), context);
return parseColumnsListFromString(random_structure, context);
}
return structure_hint;
}
return parseColumnsListFromString(structure, context);
}
StoragePtr TableFunctionGenerateRandom::executeImpl(const ASTPtr & /*ast_function*/, ContextPtr context, const std::string & table_name, ColumnsDescription /*cached_columns*/, bool is_insert_query) const
{
ColumnsDescription columns = getActualTableStructure(context, is_insert_query);
auto res = std::make_shared<StorageGenerateRandom>(
StorageID(getDatabaseName(), table_name), columns, String{}, max_array_length, max_string_length, random_seed);
res->startup();
return res;
}
void registerTableFunctionGenerate(TableFunctionFactory & factory)
{
factory.registerFunction<TableFunctionGenerateRandom>({.documentation = {}, .allow_readonly = true});
}
}
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