diff --git a/backends/postgres/test/CMakeLists.txt b/backends/postgres/test/CMakeLists.txt
index 29dcd44..96bcda9 100644
--- a/backends/postgres/test/CMakeLists.txt
+++ b/backends/postgres/test/CMakeLists.txt
@@ -3,7 +3,7 @@ CPMAddPackage("gh:catchorg/Catch2@3.7.1")
 list(APPEND CMAKE_MODULE_PATH ${catch2_SOURCE_DIR}/extras)
 
 #set(POSTGRES_CONNECTION_STRING "postgres://news:news@127.0.0.1:15432/matador")
-set(POSTGRES_CONNECTION_STRING "postgres://test:test123!@127.0.0.1:15442/matador")
+set(POSTGRES_CONNECTION_STRING "postgres://test:test123!@127.0.0.1:5432/matador")
 
 configure_file(Connection.hpp.in ${PROJECT_BINARY_DIR}/backends/postgres/test/connection.hpp @ONLY IMMEDIATE)
 
diff --git a/include/matador/query/criteria.hpp b/include/matador/query/criteria.hpp
new file mode 100644
index 0000000..f58ce6e
--- /dev/null
+++ b/include/matador/query/criteria.hpp
@@ -0,0 +1,13 @@
+#ifndef CRITERIA_CRITERIA_HPP
+#define CRITERIA_CRITERIA_HPP
+
+#include "matador/query/criteria/between_criteria.hpp"
+#include "matador/query/criteria/binary_criteria.hpp"
+#include "matador/query/criteria/collection_criteria.hpp"
+#include "matador/query/criteria/like_criteria.hpp"
+#include "matador/query/criteria/logical_criteria.hpp"
+#include "matador/query/criteria/not_criteria.hpp"
+
+#include "matador/query/criteria/criteria_operators.hpp"
+
+#endif //CRITERIA_CRITERIA_HPP
\ No newline at end of file
diff --git a/include/matador/query/criteria/abstract_criteria.hpp b/include/matador/query/criteria/abstract_criteria.hpp
new file mode 100644
index 0000000..5c5f549
--- /dev/null
+++ b/include/matador/query/criteria/abstract_criteria.hpp
@@ -0,0 +1,20 @@
+#ifndef CRITERIA_CRITERIA_NODE_HPP
+#define CRITERIA_CRITERIA_NODE_HPP
+
+#include <memory>
+
+namespace matador::query {
+
+class criteria_visitor;
+
+class abstract_criteria {
+public:
+    virtual ~abstract_criteria() = default;
+
+    virtual void accept(criteria_visitor& visitor) const = 0;
+};
+
+using criteria_ptr = std::unique_ptr<abstract_criteria>;
+
+}
+#endif //CRITERIA_CRITERIA_NODE_HPP
\ No newline at end of file
diff --git a/include/matador/query/criteria/between_criteria.hpp b/include/matador/query/criteria/between_criteria.hpp
new file mode 100644
index 0000000..f79baaa
--- /dev/null
+++ b/include/matador/query/criteria/between_criteria.hpp
@@ -0,0 +1,25 @@
+#ifndef CRITERIA_BETWEEN_CRITERIA_NODE_HPP
+#define CRITERIA_BETWEEN_CRITERIA_NODE_HPP
+
+#include "matador/query/criteria/abstract_criteria.hpp"
+
+#include "matador/sql/column.hpp"
+
+#include "matador/utils/value.hpp"
+
+namespace matador::query {
+
+class between_criteria final : public abstract_criteria {
+public:
+    between_criteria() = delete;
+    between_criteria(sql::column column, utils::value min, utils::value max);
+
+    void accept(criteria_visitor& visitor) const override;
+
+private:
+    sql::column column_;
+    utils::value min_;
+    utils::value max_;
+};
+}
+#endif //CRITERIA_BETWEEN_CRITERIA_NODE_HPP
\ No newline at end of file
diff --git a/include/matador/query/criteria/binary_criteria.hpp b/include/matador/query/criteria/binary_criteria.hpp
new file mode 100644
index 0000000..d872a72
--- /dev/null
+++ b/include/matador/query/criteria/binary_criteria.hpp
@@ -0,0 +1,33 @@
+#ifndef CRITERIA_BINARY_CRITERIA_NODE_HPP
+#define CRITERIA_BINARY_CRITERIA_NODE_HPP
+
+#include "matador/query/criteria/abstract_criteria.hpp"
+
+#include "matador/sql/column.hpp"
+
+#include "matador/utils/value.hpp"
+
+namespace matador::query {
+enum class binary_operator {
+    EQUALS,
+    NOT_EQUALS,
+    GREATER_THAN,
+    GREATER_THAN_OR_EQUAL,
+    LESS_THAN,
+    LESS_THAN_OR_EQUAL,
+};
+
+class binary_criteria final : public abstract_criteria {
+public:
+    binary_criteria() = delete;
+    binary_criteria( sql::column column, binary_operator operator_, utils::value value );
+
+    void accept( criteria_visitor& visitor ) const override;
+
+private:
+    sql::column column_;
+    binary_operator operator_{};
+    utils::value value_;
+};
+}
+#endif //CRITERIA_BINARY_CRITERIA_NODE_HPP
\ No newline at end of file
diff --git a/include/matador/query/criteria/collection_criteria.hpp b/include/matador/query/criteria/collection_criteria.hpp
new file mode 100644
index 0000000..53f3c0c
--- /dev/null
+++ b/include/matador/query/criteria/collection_criteria.hpp
@@ -0,0 +1,29 @@
+#ifndef CRITERIA_COLLECTION_CRITERIA_NODE_HPP
+#define CRITERIA_COLLECTION_CRITERIA_NODE_HPP
+
+#include "matador/query/criteria/abstract_criteria.hpp"
+
+#include "matador/sql/column.hpp"
+
+#include "matador/utils/value.hpp"
+
+namespace matador::query {
+enum class collection_operator {
+    IN,
+    OUT
+};
+
+class collection_criteria final : public abstract_criteria {
+public:
+    collection_criteria() = delete;
+    collection_criteria(sql::column col, collection_operator operator_, std::vector<utils::value> values);
+    collection_criteria(sql::column col, collection_operator operator_, std::initializer_list<utils::value> values);
+
+    void accept(criteria_visitor& visitor) const override;
+private:
+    sql::column column_;
+    collection_operator operator_;
+    std::vector<utils::value> values_;
+};
+}
+#endif //CRITERIA_COLLECTION_CRITERIA_NODE_HPP
\ No newline at end of file
diff --git a/include/matador/query/criteria/criteria_operators.hpp b/include/matador/query/criteria/criteria_operators.hpp
new file mode 100644
index 0000000..7ac98f8
--- /dev/null
+++ b/include/matador/query/criteria/criteria_operators.hpp
@@ -0,0 +1,72 @@
+#ifndef CRITERIA_CRITERIA_OPERATORS_HPP
+#define CRITERIA_CRITERIA_OPERATORS_HPP
+
+#include "matador/query/criteria/binary_criteria.hpp"
+#include "matador/query/criteria/collection_criteria.hpp"
+
+#include "matador/sql/column.hpp"
+
+#include "matador/utils/value.hpp"
+
+namespace matador::query {
+
+template<class Type>
+criteria_ptr operator==(const sql::column &col, Type val) {
+    return std::make_unique<binary_criteria>(col, binary_operator::EQUALS, val);
+}
+
+template<class Type>
+criteria_ptr operator!=(const sql::column &col, Type val) {
+    return std::make_unique<binary_criteria>(col, binary_operator::NOT_EQUALS, val);
+}
+
+template<class Type>
+criteria_ptr operator>(const sql::column &col, Type val) {
+    return std::make_unique<binary_criteria>(col, binary_operator::GREATER_THAN, val);
+}
+
+template<class Type>
+criteria_ptr operator>=(const sql::column &col, Type val) {
+    return std::make_unique<binary_criteria>(col, binary_operator::GREATER_THAN_OR_EQUAL, val);
+}
+
+template<class Type>
+criteria_ptr operator<(const sql::column &col, Type val) {
+    return std::make_unique<binary_criteria>(col, binary_operator::LESS_THAN, val);
+}
+
+template<class Type>
+criteria_ptr operator<=(const sql::column &col, Type val) {
+    return std::make_unique<binary_criteria>(col, binary_operator::LESS_THAN_OR_EQUAL, val);
+}
+
+criteria_ptr operator&&(criteria_ptr left, criteria_ptr right);
+
+criteria_ptr operator||(criteria_ptr left, criteria_ptr right);
+
+criteria_ptr operator!(criteria_ptr clause);
+
+template < class Type >
+criteria_ptr in(const sql::column &col, std::initializer_list<Type> args) {
+    std::vector<utils::value> values;
+    for ( auto &&arg : args ) {
+        values.emplace_back(std::move(arg));
+    }
+    return std::make_unique<collection_criteria>(col, collection_operator::IN, std::move(values));
+}
+
+template < class V >
+criteria_ptr out(const sql::column &col, std::initializer_list<V> args) {
+    std::vector<utils::value> values;
+    for ( auto &&arg : args ) {
+        values.emplace_back(std::move(arg));
+    }
+    return std::make_unique<collection_criteria>(col, collection_operator::OUT, values);
+}
+
+criteria_ptr between(const sql::column &col, utils::value min, utils::value max);
+
+criteria_ptr like(const sql::column &col, const std::string &pattern);
+
+}
+#endif //CRITERIA_CRITERIA_OPERATORS_HPP
\ No newline at end of file
diff --git a/include/matador/query/criteria/criteria_visitor.hpp b/include/matador/query/criteria/criteria_visitor.hpp
new file mode 100644
index 0000000..6585096
--- /dev/null
+++ b/include/matador/query/criteria/criteria_visitor.hpp
@@ -0,0 +1,24 @@
+#ifndef CRITERIA_CRITERIA_NODE_VISITOR_HPP
+#define CRITERIA_CRITERIA_NODE_VISITOR_HPP
+
+namespace matador::query {
+class between_criteria;
+class binary_criteria;
+class like_criteria;
+class logical_criteria;
+class not_criteria;
+class collection_criteria;
+
+class criteria_visitor {
+public:
+    virtual ~criteria_visitor() = default;
+
+    virtual void visit(const between_criteria &node) = 0;
+    virtual void visit(const binary_criteria &node) = 0;
+    virtual void visit(const collection_criteria &node) = 0;
+    virtual void visit(const like_criteria &node) = 0;
+    virtual void visit(const logical_criteria &node) = 0;
+    virtual void visit(const not_criteria &node) = 0;
+};
+}
+#endif //CRITERIA_CRITERIA_NODE_VISITOR_HPP
\ No newline at end of file
diff --git a/include/matador/query/criteria/like_criteria.hpp b/include/matador/query/criteria/like_criteria.hpp
new file mode 100644
index 0000000..b439723
--- /dev/null
+++ b/include/matador/query/criteria/like_criteria.hpp
@@ -0,0 +1,21 @@
+#ifndef CRITERIA_LIKE_CRITERIA_NODE_HPP
+#define CRITERIA_LIKE_CRITERIA_NODE_HPP
+
+#include "matador/query/criteria/abstract_criteria.hpp"
+
+#include "matador/sql/column.hpp"
+
+namespace matador::query {
+class like_criteria final : public abstract_criteria {
+public:
+  like_criteria() = delete;
+  like_criteria(sql::column column, std::string pattern);
+
+  void accept(criteria_visitor &visitor) const override;
+
+private:
+  sql::column column_;
+  std::string pattern_;
+};
+}
+#endif //CRITERIA_LIKE_CRITERIA_NODE_HPP
\ No newline at end of file
diff --git a/include/matador/query/criteria/logical_criteria.hpp b/include/matador/query/criteria/logical_criteria.hpp
new file mode 100644
index 0000000..ec63851
--- /dev/null
+++ b/include/matador/query/criteria/logical_criteria.hpp
@@ -0,0 +1,25 @@
+#ifndef CRITERIA_LOGICAL_CRITERIA_NODE_HPP
+#define CRITERIA_LOGICAL_CRITERIA_NODE_HPP
+
+#include "matador/query/criteria/abstract_criteria.hpp"
+
+namespace matador::query {
+enum class logical_operator {
+    AND,
+    OR,
+};
+
+class logical_criteria final : public abstract_criteria {
+public:
+    logical_criteria() = delete;
+    logical_criteria(criteria_ptr left, logical_operator op, criteria_ptr right);
+
+    void accept(criteria_visitor& visitor) const override;
+
+private:
+    std::unique_ptr<abstract_criteria> left_criteria_;
+    logical_operator operand_;
+    std::unique_ptr<abstract_criteria> right_criteria_;
+};
+}
+#endif //CRITERIA_LOGICAL_CRITERIA_NODE_HPP
\ No newline at end of file
diff --git a/include/matador/query/criteria/not_criteria.hpp b/include/matador/query/criteria/not_criteria.hpp
new file mode 100644
index 0000000..b0f583c
--- /dev/null
+++ b/include/matador/query/criteria/not_criteria.hpp
@@ -0,0 +1,18 @@
+#ifndef CRITERIA_NOT_CRITERIA_NODE_HPP
+#define CRITERIA_NOT_CRITERIA_NODE_HPP
+
+#include "matador/query/criteria/abstract_criteria.hpp"
+
+namespace matador::query {
+class not_criteria final : public abstract_criteria {
+public:
+    explicit not_criteria(criteria_ptr clause);
+
+    void accept(criteria_visitor& visitor) const override;
+
+private:
+    criteria_ptr criteria_;
+};
+}
+
+#endif //CRITERIA_NOT_CRITERIA_NODE_HPP
\ No newline at end of file
diff --git a/include/matador/query/criteria_evaluator.hpp b/include/matador/query/criteria_evaluator.hpp
new file mode 100644
index 0000000..ddc459c
--- /dev/null
+++ b/include/matador/query/criteria_evaluator.hpp
@@ -0,0 +1,28 @@
+#ifndef MATADOR_CRITERIA_EVALUATOR_HPP
+#define MATADOR_CRITERIA_EVALUATOR_HPP
+
+#include "matador/query/criteria/criteria_visitor.hpp"
+
+namespace matador::sql {
+class dialect;
+struct query_context;
+}
+
+namespace matador::query {
+
+class criteria_evaluator final : public criteria_visitor {
+public:
+  criteria_evaluator(const sql::dialect &d, sql::query_context &query);
+  void visit(const between_criteria &node) override;
+  void visit(const binary_criteria &node) override;
+  void visit(const collection_criteria &node) override;
+  void visit(const like_criteria &node) override;
+  void visit(const logical_criteria &node) override;
+  void visit(const not_criteria &node) override;
+
+private:
+  const sql::dialect &dialect_;
+  sql::query_context &query_;
+};
+}
+#endif //MATADOR_CRITERIA_EVALUATOR_HPP
\ No newline at end of file
diff --git a/source/orm/CMakeLists.txt b/source/orm/CMakeLists.txt
index 9725edc..39d106d 100644
--- a/source/orm/CMakeLists.txt
+++ b/source/orm/CMakeLists.txt
@@ -6,6 +6,14 @@ add_library(matador-orm STATIC
   ../../include/matador/orm/session_query_builder.hpp
   ../../include/matador/query/attribute_string_writer.hpp
   ../../include/matador/query/basic_condition.hpp
+  ../../include/matador/query/criteria/abstract_criteria.hpp
+  ../../include/matador/query/criteria/between_criteria.hpp
+  ../../include/matador/query/criteria/collection_criteria.hpp
+  ../../include/matador/query/criteria.hpp
+  ../../include/matador/query/criteria/criteria_operators.hpp
+  ../../include/matador/query/criteria/criteria_visitor.hpp
+  ../../include/matador/query/criteria/like_criteria.hpp
+  ../../include/matador/query/criteria/logical_criteria.hpp
   ../../include/matador/query/condition.hpp
   ../../include/matador/query/fk_value_extractor.hpp
   ../../include/matador/query/intermediates/executable_query.hpp
@@ -78,6 +86,13 @@ add_library(matador-orm STATIC
   orm/session_query_builder.cpp
   query/attribute_string_writer.cpp
   query/basic_condition.cpp
+  query/criteria/between_criteria.cpp
+  query/criteria/binary_criteria.cpp
+  query/criteria/collection_criteria.cpp
+  query/criteria/criteria_operators.cpp
+  query/criteria/like_criteria.cpp
+  query/criteria/logical_criteria.cpp
+  query/criteria/not_criteria.cpp
   query/condition.cpp
   query/intermediates/executable_query.cpp
   query/intermediates/fetchable_query.cpp
@@ -136,6 +151,8 @@ add_library(matador-orm STATIC
   sql/statement.cpp
   sql/statement_cache.cpp
   sql/table.cpp
+  ../../include/matador/query/criteria_evaluator.hpp
+  query/criteria_evaluator.cpp
 )
 
 target_include_directories(matador-orm
diff --git a/source/orm/query/criteria/between_criteria.cpp b/source/orm/query/criteria/between_criteria.cpp
new file mode 100644
index 0000000..92bf65c
--- /dev/null
+++ b/source/orm/query/criteria/between_criteria.cpp
@@ -0,0 +1,15 @@
+#include "matador/query/criteria/between_criteria.hpp"
+
+#include "matador/query/criteria/criteria_visitor.hpp"
+
+namespace matador::query{
+between_criteria::between_criteria(sql::column column, utils::value min, utils::value max )
+: column_(std::move(column))
+, min_(std::move(min))
+, max_(std::move(max))
+{}
+
+void between_criteria::accept( criteria_visitor& visitor ) const {
+    visitor.visit(*this);
+}
+}
\ No newline at end of file
diff --git a/source/orm/query/criteria/binary_criteria.cpp b/source/orm/query/criteria/binary_criteria.cpp
new file mode 100644
index 0000000..0564057
--- /dev/null
+++ b/source/orm/query/criteria/binary_criteria.cpp
@@ -0,0 +1,15 @@
+#include "matador/query/criteria/binary_criteria.hpp"
+
+#include "matador/query/criteria/criteria_visitor.hpp"
+
+namespace matador::query {
+binary_criteria::binary_criteria(sql::column column, const binary_operator operator_, utils::value value)
+: column_(std::move(column))
+, operator_(operator_)
+, value_(std::move(value))
+{}
+
+void binary_criteria::accept( criteria_visitor& visitor ) const {
+    visitor.visit(*this);
+}
+}
\ No newline at end of file
diff --git a/source/orm/query/criteria/collection_criteria.cpp b/source/orm/query/criteria/collection_criteria.cpp
new file mode 100644
index 0000000..02490f9
--- /dev/null
+++ b/source/orm/query/criteria/collection_criteria.cpp
@@ -0,0 +1,21 @@
+#include "matador/query/criteria/collection_criteria.hpp"
+
+#include "matador/query/criteria/criteria_visitor.hpp"
+
+namespace matador::query {
+collection_criteria::collection_criteria(sql::column col, collection_operator operator_, std::vector<utils::value> values )
+: column_(std::move(col))
+, operator_(operator_)
+, values_(std::move(values))
+{}
+
+collection_criteria::collection_criteria(sql::column col, const collection_operator operator_, const std::initializer_list<utils::value> values )
+: column_(std::move(col))
+, operator_(operator_)
+, values_(values)
+{}
+
+void collection_criteria::accept( criteria_visitor& visitor ) const {
+    visitor.visit(*this);
+}
+}
\ No newline at end of file
diff --git a/source/orm/query/criteria/criteria_operators.cpp b/source/orm/query/criteria/criteria_operators.cpp
new file mode 100644
index 0000000..a8aba16
--- /dev/null
+++ b/source/orm/query/criteria/criteria_operators.cpp
@@ -0,0 +1,28 @@
+#include "matador/query/criteria/criteria_operators.hpp"
+
+#include "matador/query/criteria/between_criteria.hpp"
+#include "matador/query/criteria/like_criteria.hpp"
+#include "matador/query/criteria/logical_criteria.hpp"
+#include "matador/query/criteria/not_criteria.hpp"
+
+namespace matador::query {
+criteria_ptr operator&&(criteria_ptr left, criteria_ptr right) {
+    return std::make_unique<logical_criteria>(std::move(left), logical_operator::AND, std::move(right));
+}
+
+criteria_ptr operator||(criteria_ptr left, criteria_ptr right) {
+    return std::make_unique<logical_criteria>(std::move(left), logical_operator::OR, std::move(right));
+}
+
+criteria_ptr operator!(criteria_ptr clause) {
+    return std::make_unique<not_criteria>(std::move(clause));
+}
+
+criteria_ptr between(const sql::column &col, utils::value min, utils::value max) {
+    return std::make_unique<between_criteria>(col, std::move(min), std::move(max));
+}
+
+criteria_ptr like(const sql::column &col, const std::string &pattern) {
+    return std::make_unique<like_criteria>(col, pattern);
+}
+}
diff --git a/source/orm/query/criteria/like_criteria.cpp b/source/orm/query/criteria/like_criteria.cpp
new file mode 100644
index 0000000..6ec85e4
--- /dev/null
+++ b/source/orm/query/criteria/like_criteria.cpp
@@ -0,0 +1,13 @@
+#include "matador/query/criteria/like_criteria.hpp"
+
+#include "matador/query/criteria/criteria_visitor.hpp"
+
+namespace matador::query {
+like_criteria::like_criteria(sql::column column, std::string pattern)
+: column_(std::move(column))
+, pattern_(std::move(pattern)){}
+
+void like_criteria::accept(criteria_visitor &visitor) const {
+  visitor.visit(*this);
+}
+}
diff --git a/source/orm/query/criteria/logical_criteria.cpp b/source/orm/query/criteria/logical_criteria.cpp
new file mode 100644
index 0000000..88e33a3
--- /dev/null
+++ b/source/orm/query/criteria/logical_criteria.cpp
@@ -0,0 +1,15 @@
+#include "matador/query/criteria/logical_criteria.hpp"
+
+#include "matador/query/criteria/criteria_visitor.hpp"
+
+namespace matador::query {
+logical_criteria::logical_criteria(criteria_ptr left, const logical_operator op, criteria_ptr right)
+: left_criteria_(std::move(left))
+, operand_(op)
+, right_criteria_(std::move(right))
+{}
+
+void logical_criteria::accept(criteria_visitor& visitor) const {
+    visitor.visit(*this);
+}
+}
\ No newline at end of file
diff --git a/source/orm/query/criteria/not_criteria.cpp b/source/orm/query/criteria/not_criteria.cpp
new file mode 100644
index 0000000..5fb1156
--- /dev/null
+++ b/source/orm/query/criteria/not_criteria.cpp
@@ -0,0 +1,13 @@
+#include "matador/query/criteria/not_criteria.hpp"
+
+#include "matador/query/criteria/criteria_visitor.hpp"
+
+namespace matador::query {
+not_criteria::not_criteria(criteria_ptr clause)
+: criteria_(std::move(clause))
+{}
+
+void not_criteria::accept(criteria_visitor& visitor) const {
+    visitor.visit(*this);
+}
+}
\ No newline at end of file
diff --git a/source/orm/query/criteria_evaluator.cpp b/source/orm/query/criteria_evaluator.cpp
new file mode 100644
index 0000000..ed931a5
--- /dev/null
+++ b/source/orm/query/criteria_evaluator.cpp
@@ -0,0 +1,25 @@
+#include "matador/query/criteria_evaluator.hpp"
+
+namespace matador::query {
+criteria_evaluator::criteria_evaluator(const sql::dialect &d, sql::query_context &query)
+: dialect_(d)
+, query_(query) {}
+
+void criteria_evaluator::visit(const between_criteria &node) {
+}
+
+void criteria_evaluator::visit(const binary_criteria &node) {
+}
+
+void criteria_evaluator::visit(const collection_criteria &node) {
+}
+
+void criteria_evaluator::visit(const like_criteria &node) {
+}
+
+void criteria_evaluator::visit(const logical_criteria &node) {
+}
+
+void criteria_evaluator::visit(const not_criteria &node) {
+}
+}
diff --git a/source/orm/sql/column.cpp b/source/orm/sql/column.cpp
index 128945f..6c7339c 100644
--- a/source/orm/sql/column.cpp
+++ b/source/orm/sql/column.cpp
@@ -1,13 +1,25 @@
+#include "matador/sql/column.hpp"
+
+#include "matador/sql/table.hpp"
+
+#include <stdexcept>
 #include <utility>
 
-#include "matador/sql/column.hpp"
-#include "matador/sql/table.hpp"
 
 namespace matador::sql {
 
-column operator ""_col(const char *name, size_t len)
-{
-  return column{{name, len}};
+column operator ""_col(const char *name, size_t len) {
+  const std::string str(name, len);
+  const auto pos = str.find('.');
+  if (pos == std::string::npos) {
+    return column{str};
+  }
+
+  if (str.find('.', pos + 1) != std::string::npos) {
+    throw std::invalid_argument("Invalid column name: multiple dots found");
+  }
+
+  return column{str.substr(0, pos), str.substr(pos + 1)};
 }
 
 column::column(const char *name, const std::string& as)