ClickHouse/src/Interpreters/DatabaseAndTableWithAlias.cpp
2021-01-26 10:29:11 +08:00

110 lines
3.8 KiB
C++

#include <Interpreters/DatabaseAndTableWithAlias.h>
#include <Interpreters/IdentifierSemantic.h>
#include <Interpreters/Context.h>
#include <Interpreters/getTableExpressions.h>
#include <Common/typeid_cast.h>
#include <Parsers/IAST.h>
#include <Parsers/ASTIdentifier.h>
#include <Parsers/ASTTablesInSelectQuery.h>
#include <Parsers/ASTSelectQuery.h>
#include <Parsers/ASTSubquery.h>
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
}
DatabaseAndTableWithAlias::DatabaseAndTableWithAlias(const ASTIdentifier & identifier, const String & current_database)
{
alias = identifier.tryGetAlias();
auto table_id = IdentifierSemantic::extractDatabaseAndTable(identifier);
std::tie(database, table, uuid) = std::tie(table_id.database_name, table_id.table_name, table_id.uuid);
if (database.empty())
database = current_database;
}
DatabaseAndTableWithAlias::DatabaseAndTableWithAlias(const ASTPtr & node, const String & current_database)
{
const auto * identifier = node->as<ASTIdentifier>();
if (!identifier)
throw Exception("Logical error: identifier expected", ErrorCodes::LOGICAL_ERROR);
*this = DatabaseAndTableWithAlias(*identifier, current_database);
}
DatabaseAndTableWithAlias::DatabaseAndTableWithAlias(const ASTTableExpression & table_expression, const String & current_database)
{
if (table_expression.database_and_table_name)
*this = DatabaseAndTableWithAlias(table_expression.database_and_table_name, current_database);
else if (table_expression.table_function)
alias = table_expression.table_function->tryGetAlias();
else if (table_expression.subquery)
{
const auto & cte_name = table_expression.subquery->as<const ASTSubquery &>().cte_name;
if (!cte_name.empty())
{
database = current_database;
table = cte_name;
}
alias = table_expression.subquery->tryGetAlias();
}
else
throw Exception("Logical error: no known elements in ASTTableExpression", ErrorCodes::LOGICAL_ERROR);
}
bool DatabaseAndTableWithAlias::satisfies(const DatabaseAndTableWithAlias & db_table, bool table_may_be_an_alias) const
{
/// table.*, alias.* or database.table.*
if (database.empty())
{
if (!db_table.table.empty() && table == db_table.table)
return true;
if (!db_table.alias.empty())
return (alias == db_table.alias) || (table_may_be_an_alias && table == db_table.alias);
}
return database == db_table.database && table == db_table.table;
}
String DatabaseAndTableWithAlias::getQualifiedNamePrefix(bool with_dot) const
{
if (alias.empty() && table.empty())
return "";
return (!alias.empty() ? alias : table) + (with_dot ? "." : "");
}
std::vector<DatabaseAndTableWithAlias> getDatabaseAndTables(const ASTSelectQuery & select_query, const String & current_database)
{
std::vector<const ASTTableExpression *> tables_expression = getTableExpressions(select_query);
std::vector<DatabaseAndTableWithAlias> database_and_table_with_aliases;
database_and_table_with_aliases.reserve(tables_expression.size());
for (const auto & table_expression : tables_expression)
database_and_table_with_aliases.emplace_back(DatabaseAndTableWithAlias(*table_expression, current_database));
return database_and_table_with_aliases;
}
std::optional<DatabaseAndTableWithAlias> getDatabaseAndTable(const ASTSelectQuery & select, size_t table_number)
{
const ASTTableExpression * table_expression = getTableExpression(select, table_number);
if (!table_expression)
return {};
ASTPtr database_and_table_name = table_expression->database_and_table_name;
if (!database_and_table_name || !database_and_table_name->as<ASTIdentifier>())
return {};
return DatabaseAndTableWithAlias(database_and_table_name);
}
}