Parser::CaseExpr Class Reference

#include <ParserNode.h>

Inheritance diagram for Parser::CaseExpr:

Collaboration diagram for Parser::CaseExpr:

Public Member Functions
	CaseExpr (std::list< ExprPair * > *w, Expr *e)
std::shared_ptr< Analyzer::Expr >	analyze (const Catalog_Namespace::Catalog &catalog, Analyzer::Query &query, TlistRefType allow_tlist_ref=TLIST_NONE) const override
std::string	to_string () const override
Public Member Functions inherited from Parser::Node
virtual	~Node ()

Static Public Member Functions
static std::shared_ptr < Analyzer::Expr >	normalize (const std::list< std::pair< std::shared_ptr< Analyzer::Expr >, std::shared_ptr< Analyzer::Expr >>> &, const std::shared_ptr< Analyzer::Expr >, const Executor *executor=nullptr)

Private Attributes
std::list< std::unique_ptr < ExprPair > >	when_then_list_
std::unique_ptr< Expr >	else_expr_

Additional Inherited Members
Public Types inherited from Parser::Expr
enum	TlistRefType { TLIST_NONE, TLIST_REF, TLIST_COPY }

Detailed Description

Definition at line 695 of file ParserNode.h.

Constructor & Destructor Documentation

Parser::CaseExpr::CaseExpr ( std::list< ExprPair * > *  w, Expr *  e  )

inline

Definition at line 697 of file ParserNode.h.

References CHECK, and when_then_list_.

                                           : else_expr_(e) {
    CHECK(w);
    for (const auto e : *w) {
      when_then_list_.emplace_back(e);
    }
    delete w;
  }

Member Function Documentation

std::shared_ptr< Analyzer::Expr > Parser::CaseExpr::analyze ( const Catalog_Namespace::Catalog &  catalog, Analyzer::Query &  query, TlistRefType  allow_tlist_ref = TLIST_NONE  ) const

overridevirtual

Implements Parser::Expr.

Definition at line 1052 of file ParserNode.cpp.

References kBOOLEAN.

                                        {
  SQLTypeInfo ti;
  std::list<std::pair<std::shared_ptr<Analyzer::Expr>, std::shared_ptr<Analyzer::Expr>>>
      expr_pair_list;
  for (auto& p : when_then_list_) {
    auto e1 = p->get_expr1()->analyze(catalog, query, allow_tlist_ref);
    if (e1->get_type_info().get_type() != kBOOLEAN) {
      throw std::runtime_error("Only boolean expressions can be used after WHEN.");
    }
    auto e2 = p->get_expr2()->analyze(catalog, query, allow_tlist_ref);
    expr_pair_list.emplace_back(e1, e2);
  }
  auto else_e =
      else_expr_ ? else_expr_->analyze(catalog, query, allow_tlist_ref) : nullptr;
  return normalize(expr_pair_list, else_e);
}

std::shared_ptr< Analyzer::Expr > Parser::CaseExpr::normalize ( const std::list< std::pair< std::shared_ptr< Analyzer::Expr >, std::shared_ptr< Analyzer::Expr >>> &  expr_pair_list, const std::shared_ptr< Analyzer::Expr >  else_e_in, const Executor *  executor = nullptr  )

static

Definition at line 1637 of file ParserNode.cpp.

References CHECK, Analyzer::BinOper::common_numeric_type(), Parser::common_string_type(), Parser::anonymous_namespace{ParserNode.cpp}::expr_is_null(), get_logical_type_info(), SQLTypeInfo::get_type(), SQLTypeInfo::is_boolean(), SQLTypeInfo::is_number(), SQLTypeInfo::is_string(), kENCODING_DICT, kNULLT, kTEXT, SQLTypeInfo::set_notnull(), and TRANSIENT_DICT_ID.

Referenced by QueryRewriter::rewriteColumnarDelete(), QueryRewriter::rewriteColumnarUpdate(), and RelAlgTranslator::translateCase().

                              {
  SQLTypeInfo ti;
  bool has_agg = false;
  // We need to keep track of whether there was at
  // least one none-encoded string literal expression
  // type among any of the case sub-expressions separately
  // from rest of type determination logic, as it will
  // be casted to the output dictionary type if all output
  // types are either dictionary encoded or none-encoded
  // literals, or a transient encoded dictionary if all
  // types are none-encoded (column or literal)
  SQLTypeInfo none_encoded_literal_ti;

  for (auto& p : expr_pair_list) {
    auto e1 = p.first;
    CHECK(e1->get_type_info().is_boolean());
    auto e2 = p.second;
    if (e2->get_contains_agg()) {
      has_agg = true;
    }
    const auto& e2_ti = e2->get_type_info();
    const auto col_var = std::dynamic_pointer_cast<const Analyzer::ColumnVar>(e2);
    if (e2_ti.is_string() && !e2_ti.is_dict_encoded_string() && !col_var) {
      CHECK(e2_ti.is_none_encoded_string());
      none_encoded_literal_ti =
          none_encoded_literal_ti.get_type() == kNULLT
              ? e2_ti
              : common_string_type(none_encoded_literal_ti, e2_ti, executor);
      continue;
    }
    if (ti.get_type() == kNULLT) {
      ti = e2_ti;
    } else if (e2_ti.get_type() == kNULLT) {
      ti.set_notnull(false);
      e2->set_type_info(ti);
    } else if (ti != e2_ti) {
      if (ti.is_string() && e2_ti.is_string()) {
        // Executor is needed to determine which dictionary is the largest
        // in case of two dictionary types with different encodings
        ti = common_string_type(ti, e2_ti, executor);
      } else if (ti.is_number() && e2_ti.is_number()) {
        ti = Analyzer::BinOper::common_numeric_type(ti, e2_ti);
      } else if (ti.is_boolean() && e2_ti.is_boolean()) {
        ti = Analyzer::BinOper::common_numeric_type(ti, e2_ti);
      } else {
        throw std::runtime_error(
            "Expressions in THEN clause must be of the same or compatible types.");
      }
    }
  }
  auto else_e = else_e_in;
  const auto& else_ti = else_e->get_type_info();
  if (else_e) {
    const auto col_var = std::dynamic_pointer_cast<const Analyzer::ColumnVar>(else_e);
    if (else_e->get_contains_agg()) {
      has_agg = true;
    }
    if (else_ti.is_string() && !else_ti.is_dict_encoded_string() && !col_var) {
      CHECK(else_ti.is_none_encoded_string());
      none_encoded_literal_ti =
          none_encoded_literal_ti.get_type() == kNULLT
              ? else_ti
              : common_string_type(none_encoded_literal_ti, else_ti, executor);
    } else {
      if (ti.get_type() == kNULLT) {
        ti = else_ti;
      } else if (expr_is_null(else_e.get())) {
        ti.set_notnull(false);
        else_e->set_type_info(ti);
      } else if (ti != else_ti) {
        ti.set_notnull(false);
        if (ti.is_string() && else_ti.is_string()) {
          // Executor is needed to determine which dictionary is the largest
          // in case of two dictionary types with different encodings
          ti = common_string_type(ti, else_ti, executor);
        } else if (ti.is_number() && else_ti.is_number()) {
          ti = Analyzer::BinOper::common_numeric_type(ti, else_ti);
        } else if (ti.is_boolean() && else_ti.is_boolean()) {
          ti = Analyzer::BinOper::common_numeric_type(ti, else_ti);
        } else if (get_logical_type_info(ti) != get_logical_type_info(else_ti)) {
          throw std::runtime_error(
              // types differing by encoding will be resolved at decode
              "Expressions in ELSE clause must be of the same or compatible types as "
              "those in the THEN clauses.");
        }
      }
    }
  }

  if (ti.get_type() == kNULLT && none_encoded_literal_ti.get_type() != kNULLT) {
    // If we haven't set a type so far it's because
    // every case sub-expression has a none-encoded
    // literal output. Output a transient-encoded dictionary
    // so we can use the output downstream
    ti = SQLTypeInfo(kTEXT, kENCODING_DICT, TRANSIENT_DICT_ID, kNULLT);
  }

  std::list<std::pair<std::shared_ptr<Analyzer::Expr>, std::shared_ptr<Analyzer::Expr>>>
      cast_expr_pair_list;
  for (auto p : expr_pair_list) {
    ti.set_notnull(false);
    cast_expr_pair_list.emplace_back(p.first, p.second->add_cast(ti));
  }
  if (else_e != nullptr) {
    else_e = else_e->add_cast(ti);
  } else {
    Datum d;
    // always create an else expr so that executor doesn't need to worry about it
    ti.set_notnull(false);
    else_e = makeExpr<Analyzer::Constant>(ti, true, d);
  }
  if (ti.get_type() == kNULLT) {
    throw std::runtime_error(
        "Cannot deduce the type for case expressions, all branches null");
  }

  auto case_expr = makeExpr<Analyzer::CaseExpr>(ti, has_agg, cast_expr_pair_list, else_e);
  return case_expr;
}

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std::string Parser::CaseExpr::to_string ( ) const

overridevirtual

Implements Parser::Expr.

Definition at line 1761 of file ParserNode.cpp.

                                    {
  std::string str("CASE ");
  for (auto& p : when_then_list_) {
    str += "WHEN " + p->get_expr1()->to_string() + " THEN " +
           p->get_expr2()->to_string() + " ";
  }
  if (else_expr_ != nullptr) {
    str += "ELSE " + else_expr_->to_string();
  }
  str += " END";
  return str;
}

Member Data Documentation

std::unique_ptr<Expr> Parser::CaseExpr::else_expr_

private

Definition at line 717 of file ParserNode.h.

std::list<std::unique_ptr<ExprPair> > Parser::CaseExpr::when_then_list_

private

Definition at line 716 of file ParserNode.h.

Referenced by CaseExpr().

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The documentation for this class was generated from the following files:

• /home/jenkins-slave/workspace/core-os-doxygen/Parser/ParserNode.h
• /home/jenkins-slave/workspace/core-os-doxygen/Parser/ParserNode.cpp