sqt::ExpressionLike Concept Reference

#include <sqt/orm/expression/expression_like.h>

Description

Constrains a type to be an expression-like type.

Requirements

• The type must have a static constant ParameterCount of type std::size_t, representing the number of parameters in the expression (including inline parameters and placeholders).
• The type must have a static method BuildPlaceholderBinders() with the following signature:

  auto BuildPlaceholderBinders(int parameter_index);

  The return type must satisfy the sqt::BinderTupleType concept. This method creates binders for placeholders in the expression, starting from the given parameter index.
• The type must have a static method BuildSQL() with the following signature:

  std::string BuildSQL();

  This method creates a string representing the expression in SQL.
• The type must have a member method BindInlineParameters() with the following signature:

  void BindInlineParameters(Statement& statement, int parameter_index) const;

  This method binds inline parameters in the expression to the SQL statement, starting from the given parameter index.

This concept defines the common requirements for expression-like types, which are used in various circumstances require expressions. There are several concepts for more specific expression types defined in the framework:

• sqt::AssignmentType for assignments.
• sqt::PredicateType for predicates.
• sqt::OrderingTermType for ordering terms.
• sqt::OperandType for operands.

See also

sqt::AssignmentType

sqt::BinderTupleType

sqt::OrderingTermType

sqt::OperandType

sqt::PredicateType