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#pragma once
#include <Interpreters/ExpressionActions.h>
#include <Parsers/IAST_fwd.h>
#include <Storages/ColumnsDescription.h>
namespace DB
{
/// Common structure for primary, partition and other storage keys
struct KeyDescription
{
/// User defined AST in CREATE/ALTER query. This field may be empty, but key
/// can exists because some of them maybe set implicitly (for example,
/// primary key in merge tree can be part of sorting key)
ASTPtr definition_ast;
/// ASTExpressionList with key fields, example: (x, toStartOfMonth(date))).
ASTPtr expression_list_ast;
/// Expression from expression_list_ast created by ExpressionAnalyzer. Useful,
/// when you need to get required columns for key, example: a, date, b.
ExpressionActionsPtr expression;
/// Sample block with key columns (names, types, empty column)
Block sample_block;
/// Column names in key definition, example: x, toStartOfMonth(date), a * b.
Names column_names;
/// Types from sample block ordered in columns order.
DataTypes data_types;
/// Additional key column added by storage type. Never changes after
/// initialization with non empty value. Doesn't stored in definition_ast,
/// but added to expression_list_ast and all its derivatives.
std::optional<String> additional_column;
/// Parse key structure from key definition. Requires all columns, available
/// in storage.
static KeyDescription getKeyFromAST(
const ASTPtr & definition_ast,
const ColumnsDescription & columns,
ContextPtr context);
/// Sorting key can contain additional column defined by storage type (like
/// Version column in VersionedCollapsingMergeTree).
static KeyDescription getSortingKeyFromAST(
const ASTPtr & definition_ast,
const ColumnsDescription & columns,
ContextPtr context,
const std::optional<String> & additional_column);
/// Build an empty key description. It's different from the default constructor with some
/// additional initializations.
static KeyDescription buildEmptyKey();
/// Recalculate all expressions and fields for key with new columns without
/// changes in constant fields. Just wrapper for static methods.
void recalculateWithNewColumns(
const ColumnsDescription & new_columns,
ContextPtr context);
/// Recalculate all expressions and fields for key with new ast without
/// changes in constant fields. Just wrapper for static methods.
void recalculateWithNewAST(
const ASTPtr & new_ast,
const ColumnsDescription & columns,
ContextPtr context);
KeyDescription() = default;
/// We need custom copy constructors because we don't want
/// unintentionaly share AST variables and modify them.
KeyDescription(const KeyDescription & other);
KeyDescription & operator=(const KeyDescription & other);
/// Substitute modulo with moduloLegacy. Used in KeyCondition to allow proper comparison with keys.
static bool moduloToModuloLegacyRecursive(ASTPtr node_expr);
/// Parse description from string
static KeyDescription parse(const String & str, const ColumnsDescription & columns, ContextPtr context);
};
}
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