ClickHouse/dbms/src/Interpreters/IdentifierSemantic.cpp

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#include <Common/typeid_cast.h>
#include <Interpreters/IdentifierSemantic.h>
namespace DB
{
std::optional<String> IdentifierSemantic::getColumnName(const ASTIdentifier & node)
{
if (!node.semantic->special)
return node.name;
return {};
}
std::optional<String> IdentifierSemantic::getColumnName(const ASTPtr & ast)
{
if (ast)
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if (const auto * id = ast->as<ASTIdentifier>())
if (!id->semantic->special)
return id->name;
return {};
}
std::optional<String> IdentifierSemantic::getTableName(const ASTIdentifier & node)
{
if (node.semantic->special)
return node.name;
return {};
}
std::optional<String> IdentifierSemantic::getTableName(const ASTPtr & ast)
{
if (ast)
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if (const auto * id = ast->as<ASTIdentifier>())
if (id->semantic->special)
return id->name;
return {};
}
void IdentifierSemantic::setNeedLongName(ASTIdentifier & identifier, bool value)
{
identifier.semantic->need_long_name = value;
}
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bool IdentifierSemantic::canBeAlias(const ASTIdentifier & identifier)
{
return identifier.semantic->can_be_alias;
}
void IdentifierSemantic::setMembership(ASTIdentifier & identifier, size_t table_no)
{
identifier.semantic->membership = table_no;
}
size_t IdentifierSemantic::getMembership(const ASTIdentifier & identifier)
{
return identifier.semantic->membership;
}
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std::pair<String, String> IdentifierSemantic::extractDatabaseAndTable(const ASTIdentifier & identifier)
{
if (identifier.name_parts.size() > 2)
throw Exception("Logical error: more than two components in table expression", ErrorCodes::LOGICAL_ERROR);
if (identifier.name_parts.size() == 2)
return { identifier.name_parts[0], identifier.name_parts[1] };
return { "", identifier.name };
}
bool IdentifierSemantic::doesIdentifierBelongTo(const ASTIdentifier & identifier, const String & database, const String & table)
{
size_t num_components = identifier.name_parts.size();
if (num_components >= 3)
return identifier.name_parts[0] == database &&
identifier.name_parts[1] == table;
return false;
}
bool IdentifierSemantic::doesIdentifierBelongTo(const ASTIdentifier & identifier, const String & table)
{
size_t num_components = identifier.name_parts.size();
if (num_components >= 2)
return identifier.name_parts[0] == table;
return false;
}
size_t IdentifierSemantic::canReferColumnToTable(const ASTIdentifier & identifier, const DatabaseAndTableWithAlias & db_and_table)
{
/// database.table.column
if (doesIdentifierBelongTo(identifier, db_and_table.database, db_and_table.table))
return 2;
/// table.column or alias.column.
if (doesIdentifierBelongTo(identifier, db_and_table.table) ||
doesIdentifierBelongTo(identifier, db_and_table.alias))
return 1;
return 0;
}
/// Checks that ast is ASTIdentifier and remove num_qualifiers_to_strip components from left.
/// Example: 'database.table.name' -> (num_qualifiers_to_strip = 2) -> 'name'.
void IdentifierSemantic::setColumnShortName(ASTIdentifier & identifier, size_t to_strip)
{
if (!to_strip)
return;
std::vector<String> stripped(identifier.name_parts.begin() + to_strip, identifier.name_parts.end());
DB::String new_name;
for (const auto & part : stripped)
{
if (!new_name.empty())
new_name += '.';
new_name += part;
}
identifier.name.swap(new_name);
}
void IdentifierSemantic::setColumnNormalName(ASTIdentifier & identifier, const DatabaseAndTableWithAlias & db_and_table)
{
size_t match = IdentifierSemantic::canReferColumnToTable(identifier, db_and_table);
setColumnShortName(identifier, match);
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if (match)
identifier.semantic->can_be_alias = false;
if (identifier.semantic->need_long_name)
setColumnLongName(identifier, db_and_table);
}
void IdentifierSemantic::setColumnLongName(ASTIdentifier & identifier, const DatabaseAndTableWithAlias & db_and_table)
{
String prefix = db_and_table.getQualifiedNamePrefix();
if (!prefix.empty())
{
String short_name = identifier.shortName();
identifier.name = prefix + short_name;
prefix.resize(prefix.size() - 1); /// crop dot
identifier.name_parts = {prefix, short_name};
}
}
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String IdentifierSemantic::columnNormalName(const ASTIdentifier & identifier, const DatabaseAndTableWithAlias & db_and_table)
{
ASTPtr copy = identifier.clone();
setColumnNormalName(copy->as<ASTIdentifier &>(), db_and_table);
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return copy->getAliasOrColumnName();
}
String IdentifierSemantic::columnLongName(const ASTIdentifier & identifier, const DatabaseAndTableWithAlias & db_and_table)
{
return db_and_table.getQualifiedNamePrefix() + identifier.shortName();
}
}