src/knowledge_base.cpp

@@ -1,18 +1,16 @@
 #include "knowledge_base.h"
 #include "models/action.h"
 #include "models/entity.h"
+#include "models/error.h"
 #include "models/fact.h"
 #include "models/rule.h"
 #include "models/suggest_action.h"
 #include "models/verb.h"
 
+#include <cstring>
 #include <filesystem>
 #include <iostream>
-
+#include <string>
-obelisk::KnowledgeBase::KnowledgeBase(const char* filename)
-{
-    KnowledgeBase(filename, DEFAULT_FLAGS);
-}
 
 obelisk::KnowledgeBase::KnowledgeBase(const char* filename, int flags)
 {
@@ -28,6 +26,8 @@ obelisk::KnowledgeBase::KnowledgeBase(const char* filename, int flags)
         logSqliteError(result);
     }
 
+    enableForeignKeys();
+
     if (!dbExists)
     {
         createTable(obelisk::Action::createTable);
@@ -47,16 +47,25 @@ obelisk::KnowledgeBase::~KnowledgeBase()
     }
 }
 
-void obelisk::KnowledgeBase::createTable(std::function<const char*()> function)
+/**
+ * @brief Enable foreign key functionality in the open database.
+ *
+ * This must always be done when the connection is opened or it will not
+ * enforce the foreign key constraints.
+ */
+void obelisk::KnowledgeBase::enableForeignKeys()
 {
-    char* tmp;
+    char* errmsg;
-    auto result = sqlite3_exec(dbConnection_, function(), NULL, NULL, &tmp);
+    int result = sqlite3_exec(dbConnection_,
+        "PRAGMA foreign_keys = ON;",
+        NULL,
+        NULL,
+        &errmsg);
     if (result != SQLITE_OK)
     {
         logSqliteError(result);
-        if (tmp)
+        if (errmsg)
         {
-            std::string errmsg(tmp);
             throw obelisk::KnowledgeBaseException(errmsg);
         }
         else
@@ -66,7 +75,103 @@ void obelisk::KnowledgeBase::createTable(std::function<const char*()> function)
     }
 }
 
-// TODO: log files?
+void obelisk::KnowledgeBase::createTable(std::function<const char*()> function)
+{
+    char* errmsg;
+    int result = sqlite3_exec(dbConnection_, function(), NULL, NULL, &errmsg);
+    if (result != SQLITE_OK)
+    {
+        logSqliteError(result);
+        if (errmsg)
+        {
+            throw obelisk::KnowledgeBaseException(errmsg);
+        }
+        else
+        {
+            throw obelisk::KnowledgeBaseException();
+        }
+    }
+}
+
+void obelisk::KnowledgeBase::addEntities(std::vector<obelisk::Entity>& entities)
+{
+    for (auto& entity : entities)
+    {
+        try
+        {
+            entity.insertEntity(dbConnection_);
+        }
+        catch (obelisk::DatabaseException::ConstraintException& exception)
+        {
+            // ignore unique constraint error
+            if (std::strcmp(exception.what(),
+                    "UNIQUE constraint failed: entity.name")
+                != 0)
+            {
+                throw;
+            }
+        }
+    }
+}
+
+void obelisk::KnowledgeBase::addVerbs(std::vector<obelisk::Verb>& verbs)
+{
+    for (auto& verb : verbs)
+    {
+        try
+        {
+            verb.insertVerb(dbConnection_);
+        }
+        catch (obelisk::DatabaseException::ConstraintException& exception)
+        {
+            // ignore unique constraint error
+            if (std::strcmp(exception.what(),
+                    "UNIQUE constraint failed: verb.name")
+                != 0)
+            {
+                throw;
+            }
+        }
+    }
+}
+
+void obelisk::KnowledgeBase::addFacts(std::vector<obelisk::Fact>& facts)
+{
+    for (auto& fact : facts)
+    {
+        try
+        {
+            fact.insertFact(dbConnection_);
+        }
+        catch (obelisk::DatabaseException::ConstraintException& exception)
+        {
+            // ignore unique constraint error
+            if (std::strcmp(exception.what(),
+                    "UNIQUE constraint failed: fact.left_entity, fact.right_entity, fact.verb")
+                != 0)
+            {
+                throw;
+            }
+        }
+    }
+}
+
+void obelisk::KnowledgeBase::getEntity(obelisk::Entity& entity)
+{
+    entity.selectEntity(dbConnection_);
+}
+
+void obelisk::KnowledgeBase::getVerb(obelisk::Verb& verb)
+{
+    verb.selectVerb(dbConnection_);
+}
+
+void obelisk::KnowledgeBase::getFact(obelisk::Fact& fact)
+{
+    fact.selectFact(dbConnection_);
+}
+
+// TODO: log files? or just throw an error?
 void obelisk::KnowledgeBase::logSqliteError(int result)
 {
     std::cout << sqlite3_errstr(result) << std::endl;

src/knowledge_base.h

@@ -1,10 +1,15 @@
 #ifndef OBELISK_KNOWLEDGE_BASE_H
 #define OBELISK_KNOWLEDGE_BASE_H
 
+#include "models/entity.h"
+#include "models/fact.h"
+#include "models/verb.h"
+
 #include <sqlite3.h>
 
 #include <functional>
 #include <iostream>
+#include <memory>
 #include <string>
 
 namespace obelisk
@@ -19,19 +24,27 @@ namespace obelisk
             int flags_;
             void logSqliteError(int result);
 
+            void enableForeignKeys();
             void createTable(std::function<const char*()> function);
 
         public:
-            KnowledgeBase(const char* filename);
             KnowledgeBase(const char* filename, int flags);
+
+            KnowledgeBase(const char* filename) :
+                KnowledgeBase(filename,
+                    SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE)
+            {
+            }
+
             ~KnowledgeBase();
 
-            template<typename T, typename U>
+            void addEntities(std::vector<obelisk::Entity>& entities);
-            int addFacts(std::string verb, T leftEntities, U rightEntities);
+            void addVerbs(std::vector<obelisk::Verb>& verbs);
-            // TODO: add parameter for fact
+            void addFacts(std::vector<obelisk::Fact>& facts);
-            template<typename T, typename U>
+
-            int addRules(std::string verb, T leftEntities, U rightEntities);
+            void getEntity(obelisk::Entity& entity);
-            template<typename T, typename U> int addActions();
+            void getVerb(obelisk::Verb& verb);
+            void getFact(obelisk::Fact& fact);
 
             void getDouble(double& result, float var1, float var2);
             void getFloat(float& result1, float& result2, double var);

src/models/action.cpp

@@ -11,7 +11,7 @@ const char* obelisk::Action::createTable()
     )";
 }
 
-int obelisk::Action::getId()
+int& obelisk::Action::getId()
 {
     return id_;
 }
@@ -21,7 +21,7 @@ void obelisk::Action::setId(int id)
     id_ = id;
 }
 
-std::string obelisk::Action::getName()
+std::string& obelisk::Action::getName()
 {
     return name_;
 }

src/models/action.h

@@ -38,10 +38,10 @@ namespace obelisk
 
             static const char* createTable();
 
-            int getId();
+            int& getId();
             void setId(int id);
 
-            std::string getName();
+            std::string& getName();
             void setName(std::string name);
     };
 } // namespace obelisk

src/models/entity.cpp

@@ -1,4 +1,5 @@
 #include "models/entity.h"
+#include "models/error.h"
 
 const char* obelisk::Entity::createTable()
 {
@@ -11,7 +12,142 @@ const char* obelisk::Entity::createTable()
     )";
 }
 
-int obelisk::Entity::getId()
+void obelisk::Entity::selectEntity(sqlite3* dbConnection)
+{
+    if (dbConnection == nullptr)
+    {
+        throw obelisk::DatabaseException("database isn't open");
+    }
+
+    sqlite3_stmt* ppStmt = nullptr;
+
+    auto result = sqlite3_prepare_v2(dbConnection,
+        "SELECT id, name FROM entity WHERE name=?",
+        -1,
+        &ppStmt,
+        nullptr);
+
+    if (result != SQLITE_OK)
+    {
+        throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+    }
+
+    result = sqlite3_bind_text(ppStmt, 1, getName().c_str(), -1, SQLITE_STATIC);
+    switch (result)
+    {
+        case SQLITE_OK :
+            break;
+        case SQLITE_TOOBIG :
+            throw obelisk::DatabaseException::SizeException();
+            break;
+        case SQLITE_RANGE :
+            throw obelisk::DatabaseException::RangeException();
+            break;
+        case SQLITE_NOMEM :
+            throw obelisk::DatabaseException::MemoryException();
+            break;
+        default :
+            throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+            break;
+    }
+
+    result = sqlite3_step(ppStmt);
+    switch (result)
+    {
+        case SQLITE_DONE :
+            // no rows in the database
+            break;
+        case SQLITE_ROW :
+            setId(sqlite3_column_int(ppStmt, 0));
+            setName((char*) sqlite3_column_text(ppStmt, 1));
+            break;
+        case SQLITE_BUSY :
+            throw obelisk::DatabaseException::BusyException();
+            break;
+        case SQLITE_MISUSE :
+            throw obelisk::DatabaseException::MisuseException();
+            break;
+        default :
+            throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+            break;
+    }
+
+    result = sqlite3_finalize(ppStmt);
+
+    if (result != SQLITE_OK)
+    {
+        throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+    }
+}
+
+void obelisk::Entity::insertEntity(sqlite3* dbConnection)
+{
+    if (dbConnection == nullptr)
+    {
+        throw obelisk::DatabaseException("database isn't open");
+    }
+
+    sqlite3_stmt* ppStmt = nullptr;
+
+    auto result = sqlite3_prepare_v2(dbConnection,
+        "INSERT INTO entity (name) VALUES (?)",
+        -1,
+        &ppStmt,
+        nullptr);
+    if (result != SQLITE_OK)
+    {
+        throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+    }
+
+    result
+        = sqlite3_bind_text(ppStmt, 1, getName().c_str(), -1, SQLITE_TRANSIENT);
+    switch (result)
+    {
+        case SQLITE_OK :
+            break;
+        case SQLITE_TOOBIG :
+            throw obelisk::DatabaseException::SizeException();
+            break;
+        case SQLITE_RANGE :
+            throw obelisk::DatabaseException::RangeException();
+            break;
+        case SQLITE_NOMEM :
+            throw obelisk::DatabaseException::MemoryException();
+            break;
+        default :
+            throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+            break;
+    }
+
+    result = sqlite3_step(ppStmt);
+    switch (result)
+    {
+        case SQLITE_DONE :
+            setId((int) sqlite3_last_insert_rowid(dbConnection));
+            sqlite3_set_last_insert_rowid(dbConnection, 0);
+            break;
+        case SQLITE_CONSTRAINT :
+            throw obelisk::DatabaseException::ConstraintException(
+                sqlite3_errmsg(dbConnection));
+        case SQLITE_BUSY :
+            throw obelisk::DatabaseException::BusyException();
+            break;
+        case SQLITE_MISUSE :
+            throw obelisk::DatabaseException::MisuseException();
+            break;
+        default :
+            throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+            break;
+    }
+
+    result = sqlite3_finalize(ppStmt);
+    if (result != SQLITE_OK)
+    {
+        throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+    }
+}
+
+int& obelisk::Entity::getId()
 {
     return id_;
 }
@@ -21,7 +157,7 @@ void obelisk::Entity::setId(int id)
     id_ = id;
 }
 
-std::string obelisk::Entity::getName()
+std::string& obelisk::Entity::getName()
 {
     return name_;
 }

src/models/entity.h

@@ -1,6 +1,8 @@
 #ifndef OBELISK_MODELS_ENTITY_H
 #define OBELISK_MODELS_ENTITY_H
 
+#include <sqlite3.h>
+
 #include <string>
 
 namespace obelisk
@@ -38,11 +40,14 @@ namespace obelisk
 
             static const char* createTable();
 
-            int getId();
+            int& getId();
             void setId(int id);
 
-            std::string getName();
+            std::string& getName();
             void setName(std::string name);
+
+            void selectEntity(sqlite3* dbConnection);
+            void insertEntity(sqlite3* dbConnection);
     };
 } // namespace obelisk
 

src/models/error.h

@@ -0,0 +1,146 @@
+#ifndef OBELISK_MODELS_ERROR_H
+#define OBELISK_MODELS_ERROR_H
+
+#include <exception>
+#include <string>
+
+namespace obelisk
+{
+    class DatabaseException : public std::exception
+    {
+        private:
+            const std::string errorMessage_;
+
+        public:
+            DatabaseException() :
+                errorMessage_("an unknown error ocurred")
+            {
+            }
+
+            DatabaseException(const int errorCode) :
+                errorMessage_(
+                    "database error " + std::to_string(errorCode) + " ocurred")
+            {
+            }
+
+            DatabaseException(const std::string& errorMessage) :
+                errorMessage_(errorMessage)
+            {
+            }
+
+            const char* what() const noexcept
+            {
+                return errorMessage_.c_str();
+            }
+
+            class SizeException : public std::exception
+            {
+                private:
+                    const std::string errorMessage_;
+
+                public:
+                    SizeException() :
+                        errorMessage_("size of string or blob exceeds limits")
+                    {
+                    }
+
+                    const char* what() const noexcept
+                    {
+                        return errorMessage_.c_str();
+                    }
+            };
+
+            class RangeException : public std::exception
+            {
+                private:
+                    const std::string errorMessage_;
+
+                public:
+                    RangeException() :
+                        errorMessage_("parameter index is out of range")
+                    {
+                    }
+
+                    const char* what() const noexcept
+                    {
+                        return errorMessage_.c_str();
+                    }
+            };
+
+            class MemoryException : public std::exception
+            {
+                private:
+                    const std::string errorMessage_;
+
+                public:
+                    MemoryException() :
+                        errorMessage_("not enough memory for operation")
+                    {
+                    }
+
+                    const char* what() const noexcept
+                    {
+                        return errorMessage_.c_str();
+                    }
+            };
+
+            class BusyException : public std::exception
+            {
+                private:
+                    const std::string errorMessage_;
+
+                public:
+                    BusyException() :
+                        errorMessage_(
+                            "database was busy and operation not performed")
+                    {
+                    }
+
+                    const char* what() const noexcept
+                    {
+                        return errorMessage_.c_str();
+                    }
+            };
+
+            class MisuseException : public std::exception
+            {
+                private:
+                    const std::string errorMessage_;
+
+                public:
+                    MisuseException() :
+                        errorMessage_("misuse of the database routine")
+                    {
+                    }
+
+                    const char* what() const noexcept
+                    {
+                        return errorMessage_.c_str();
+                    }
+            };
+
+            class ConstraintException : public std::exception
+            {
+                private:
+                    const std::string errorMessage_;
+
+                public:
+                    ConstraintException() :
+                        errorMessage_("a constraint exception occurred")
+                    {
+                    }
+
+                    ConstraintException(const std::string& errorMessage) :
+                        errorMessage_(errorMessage)
+                    {
+                    }
+
+                    const char* what() const noexcept
+                    {
+                        return errorMessage_.c_str();
+                    }
+            };
+    };
+} // namespace obelisk
+
+#endif

src/models/fact.cpp

@@ -1,3 +1,4 @@
+#include "models/error.h"
 #include "models/fact.h"
 
 const char* obelisk::Fact::createTable()
@@ -9,6 +10,7 @@ const char* obelisk::Fact::createTable()
             "right_entity" INTEGER NOT NULL,
             "verb"         INTEGER NOT NULL,
             PRIMARY KEY("id" AUTOINCREMENT),
+            UNIQUE("left_entity", "right_entity", "verb")
             FOREIGN KEY("verb") REFERENCES "verb"("id") ON DELETE RESTRICT,
             FOREIGN KEY("right_entity") REFERENCES "entity"("id") ON DELETE RESTRICT,
             FOREIGN KEY("left_entity") REFERENCES "entity"("id") ON DELETE RESTRICT
@@ -16,7 +18,217 @@ const char* obelisk::Fact::createTable()
     )";
 }
 
-int obelisk::Fact::getId()
+void obelisk::Fact::selectFact(sqlite3* dbConnection)
+{
+    if (dbConnection == nullptr)
+    {
+        throw obelisk::DatabaseException("database isn't open");
+    }
+
+    sqlite3_stmt* ppStmt = nullptr;
+
+    auto result = sqlite3_prepare_v2(dbConnection,
+        "SELECT id, left_entity, right_entity, verb FROM fact WHERE (left_entity=? AND right_entity=? AND verb=?)",
+        -1,
+        &ppStmt,
+        nullptr);
+    if (result != SQLITE_OK)
+    {
+        throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+    }
+
+    result = sqlite3_bind_int(ppStmt, 1, getLeftEntity().getId());
+    switch (result)
+    {
+        case SQLITE_OK :
+            break;
+        case SQLITE_TOOBIG :
+            throw obelisk::DatabaseException::SizeException();
+            break;
+        case SQLITE_RANGE :
+            throw obelisk::DatabaseException::RangeException();
+            break;
+        case SQLITE_NOMEM :
+            throw obelisk::DatabaseException::MemoryException();
+            break;
+        default :
+            throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+            break;
+    }
+
+    result = sqlite3_bind_int(ppStmt, 2, getRightEntity().getId());
+    switch (result)
+    {
+        case SQLITE_OK :
+            break;
+        case SQLITE_TOOBIG :
+            throw obelisk::DatabaseException::SizeException();
+            break;
+        case SQLITE_RANGE :
+            throw obelisk::DatabaseException::RangeException();
+            break;
+        case SQLITE_NOMEM :
+            throw obelisk::DatabaseException::MemoryException();
+            break;
+        default :
+            throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+            break;
+    }
+
+    result = sqlite3_bind_int(ppStmt, 3, getVerb().getId());
+    switch (result)
+    {
+        case SQLITE_OK :
+            break;
+        case SQLITE_TOOBIG :
+            throw obelisk::DatabaseException::SizeException();
+            break;
+        case SQLITE_RANGE :
+            throw obelisk::DatabaseException::RangeException();
+            break;
+        case SQLITE_NOMEM :
+            throw obelisk::DatabaseException::MemoryException();
+            break;
+        default :
+            throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+            break;
+    }
+
+    result = sqlite3_step(ppStmt);
+    switch (result)
+    {
+        case SQLITE_DONE :
+            // no rows in the database
+            break;
+        case SQLITE_ROW :
+            setId(sqlite3_column_int(ppStmt, 0));
+            getLeftEntity().setId(sqlite3_column_int(ppStmt, 1));
+            getRightEntity().setId(sqlite3_column_int(ppStmt, 2));
+            getVerb().setId(sqlite3_column_int(ppStmt, 3));
+            break;
+        case SQLITE_BUSY :
+            throw obelisk::DatabaseException::BusyException();
+            break;
+        case SQLITE_MISUSE :
+            throw obelisk::DatabaseException::MisuseException();
+            break;
+        default :
+            throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+            break;
+    }
+
+    result = sqlite3_finalize(ppStmt);
+    if (result != SQLITE_OK)
+    {
+        throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+    }
+}
+
+void obelisk::Fact::insertFact(sqlite3* dbConnection)
+{
+    if (dbConnection == nullptr)
+    {
+        throw obelisk::DatabaseException("database isn't open");
+    }
+
+    sqlite3_stmt* ppStmt = nullptr;
+
+    auto result = sqlite3_prepare_v2(dbConnection,
+        "INSERT INTO fact (left_entity, right_entity, verb) VALUES (?, ?, ?)",
+        -1,
+        &ppStmt,
+        nullptr);
+    if (result != SQLITE_OK)
+    {
+        throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+    }
+
+    result = sqlite3_bind_int(ppStmt, 1, getLeftEntity().getId());
+    switch (result)
+    {
+        case SQLITE_OK :
+            break;
+        case SQLITE_TOOBIG :
+            throw obelisk::DatabaseException::SizeException();
+            break;
+        case SQLITE_RANGE :
+            throw obelisk::DatabaseException::RangeException();
+            break;
+        case SQLITE_NOMEM :
+            throw obelisk::DatabaseException::MemoryException();
+            break;
+        default :
+            throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+            break;
+    }
+
+    result = sqlite3_bind_int(ppStmt, 2, getRightEntity().getId());
+    switch (result)
+    {
+        case SQLITE_OK :
+            break;
+        case SQLITE_TOOBIG :
+            throw obelisk::DatabaseException::SizeException();
+            break;
+        case SQLITE_RANGE :
+            throw obelisk::DatabaseException::RangeException();
+            break;
+        case SQLITE_NOMEM :
+            throw obelisk::DatabaseException::MemoryException();
+            break;
+        default :
+            throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+            break;
+    }
+
+    result = sqlite3_bind_int(ppStmt, 3, getVerb().getId());
+    switch (result)
+    {
+        case SQLITE_OK :
+            break;
+        case SQLITE_TOOBIG :
+            throw obelisk::DatabaseException::SizeException();
+            break;
+        case SQLITE_RANGE :
+            throw obelisk::DatabaseException::RangeException();
+            break;
+        case SQLITE_NOMEM :
+            throw obelisk::DatabaseException::MemoryException();
+            break;
+        default :
+            throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+            break;
+    }
+
+    result = sqlite3_step(ppStmt);
+    switch (result)
+    {
+        case SQLITE_DONE :
+            setId((int) sqlite3_last_insert_rowid(dbConnection));
+            sqlite3_set_last_insert_rowid(dbConnection, 0);
+            break;
+        case SQLITE_CONSTRAINT :
+            throw obelisk::DatabaseException::ConstraintException(
+                sqlite3_errmsg(dbConnection));
+        case SQLITE_BUSY :
+            throw obelisk::DatabaseException::BusyException();
+            break;
+        case SQLITE_MISUSE :
+            throw obelisk::DatabaseException::MisuseException();
+            break;
+        default :
+            throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+            break;
+    }
+
+    result = sqlite3_finalize(ppStmt);
+    if (result != SQLITE_OK)
+    {
+        throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+    }
+}
+
+int& obelisk::Fact::getId()
 {
     return id_;
 }
@@ -26,7 +238,7 @@ void obelisk::Fact::setId(int id)
     id_ = id;
 }
 
-obelisk::Entity obelisk::Fact::getLeftEntity()
+obelisk::Entity& obelisk::Fact::getLeftEntity()
 {
     return leftEntity_;
 }
@@ -36,7 +248,7 @@ void obelisk::Fact::setLeftEntity(obelisk::Entity leftEntity)
     leftEntity_ = leftEntity;
 }
 
-obelisk::Entity obelisk::Fact::getRightEntity()
+obelisk::Entity& obelisk::Fact::getRightEntity()
 {
     return rightEntity_;
 }
@@ -46,7 +258,7 @@ void obelisk::Fact::setRightEntity(obelisk::Entity rightEntity)
     rightEntity_ = rightEntity;
 }
 
-obelisk::Verb obelisk::Fact::getVerb()
+obelisk::Verb& obelisk::Fact::getVerb()
 {
     return verb_;
 }

src/models/fact.h

@@ -2,6 +2,7 @@
 #define OBELISK_MODELS_FACT_H
 
 #include "models/entity.h"
+#include "models/fact.h"
 #include "models/verb.h"
 
 #include <string>
@@ -56,17 +57,20 @@ namespace obelisk
 
             static const char* createTable();
 
-            int getId();
+            int& getId();
             void setId(int id);
 
-            obelisk::Entity getLeftEntity();
+            Entity& getLeftEntity();
             void setLeftEntity(obelisk::Entity leftEntity);
 
-            obelisk::Entity getRightEntity();
+            Entity& getRightEntity();
             void setRightEntity(obelisk::Entity leftEntity);
 
-            obelisk::Verb getVerb();
+            Verb& getVerb();
             void setVerb(obelisk::Verb verb);
+
+            void selectFact(sqlite3* dbConnection);
+            void insertFact(sqlite3* dbConnection);
     };
 } // namespace obelisk
 

src/models/rule.cpp

@@ -8,13 +8,14 @@ const char* obelisk::Rule::createTable()
             "fact"   INTEGER NOT NULL,
             "reason" INTEGER NOT NULL CHECK("reason" != "fact"),
             PRIMARY KEY("id" AUTOINCREMENT),
+            UNIQUE("fact", "reason"),
             FOREIGN KEY("fact") REFERENCES "fact"("id") ON DELETE RESTRICT,
             FOREIGN KEY("reason") REFERENCES "fact"("id") ON DELETE RESTRICT
         );
     )";
 }
 
-int obelisk::Rule::getId()
+int& obelisk::Rule::getId()
 {
     return id_;
 }
@@ -24,7 +25,7 @@ void obelisk::Rule::setId(int id)
     id_ = id;
 }
 
-obelisk::Fact obelisk::Rule::getFact()
+obelisk::Fact& obelisk::Rule::getFact()
 {
     return fact_;
 }
@@ -34,7 +35,7 @@ void obelisk::Rule::setFact(obelisk::Fact fact)
     fact_ = fact;
 }
 
-obelisk::Fact obelisk::Rule::getReason()
+obelisk::Fact& obelisk::Rule::getReason()
 {
     return reason_;
 }

src/models/rule.h

@@ -45,13 +45,13 @@ namespace obelisk
 
             static const char* createTable();
 
-            int getId();
+            int& getId();
             void setId(int id);
 
-            obelisk::Fact getFact();
+            obelisk::Fact& getFact();
             void setFact(obelisk::Fact fact);
 
-            obelisk::Fact getReason();
+            obelisk::Fact& getReason();
             void setReason(obelisk::Fact reason);
     };
 } // namespace obelisk

src/models/suggest_action.cpp

@@ -9,6 +9,7 @@ const char* obelisk::SuggestAction::createTable()
             "true_action"  INTEGER NOT NULL,
             "false_action" INTEGER NOT NULL,
             PRIMARY KEY("id" AUTOINCREMENT),
+            UNIQUE("fact", "true_action", "false_action"),
             FOREIGN KEY("fact") REFERENCES "fact"("id") ON DELETE RESTRICT,
             FOREIGN KEY("true_action") REFERENCES "action"("id") ON DELETE RESTRICT,
             FOREIGN KEY("false_action") REFERENCES "action"("id") ON DELETE RESTRICT
@@ -16,7 +17,7 @@ const char* obelisk::SuggestAction::createTable()
     )";
 }
 
-int obelisk::SuggestAction::getId()
+int& obelisk::SuggestAction::getId()
 {
     return id_;
 }
@@ -26,7 +27,7 @@ void obelisk::SuggestAction::setId(int id)
     id_ = id;
 }
 
-obelisk::Fact obelisk::SuggestAction::getFact()
+obelisk::Fact& obelisk::SuggestAction::getFact()
 {
     return fact_;
 }
@@ -36,7 +37,7 @@ void obelisk::SuggestAction::setFact(obelisk::Fact fact)
     fact_ = fact;
 }
 
-obelisk::Action obelisk::SuggestAction::getTrueAction()
+obelisk::Action& obelisk::SuggestAction::getTrueAction()
 {
     return trueAction_;
 }
@@ -46,7 +47,7 @@ void obelisk::SuggestAction::setTrueAction(obelisk::Action trueAction)
     trueAction_ = trueAction;
 }
 
-obelisk::Action obelisk::SuggestAction::getFalseAction()
+obelisk::Action& obelisk::SuggestAction::getFalseAction()
 {
     return falseAction_;
 }

src/models/suggest_action.h

@@ -56,16 +56,16 @@ namespace obelisk
 
             static const char* createTable();
 
-            int getId();
+            int& getId();
             void setId(int id);
 
-            obelisk::Fact getFact();
+            obelisk::Fact& getFact();
             void setFact(obelisk::Fact fact);
 
-            obelisk::Action getTrueAction();
+            obelisk::Action& getTrueAction();
             void setTrueAction(obelisk::Action trueAction);
 
-            obelisk::Action getFalseAction();
+            obelisk::Action& getFalseAction();
             void setFalseAction(obelisk::Action falseAction);
     };
 } // namespace obelisk

src/models/verb.cpp

@@ -1,5 +1,8 @@
+#include "models/error.h"
 #include "models/verb.h"
 
+#include <iostream>
+
 const char* obelisk::Verb::createTable()
 {
     return R"(
@@ -11,7 +14,140 @@ const char* obelisk::Verb::createTable()
     )";
 }
 
-int obelisk::Verb::getId()
+void obelisk::Verb::selectVerb(sqlite3* dbConnection)
+{
+    if (dbConnection == nullptr)
+    {
+        throw obelisk::DatabaseException("database isn't open");
+    }
+
+    sqlite3_stmt* ppStmt = nullptr;
+
+    auto result = sqlite3_prepare_v2(dbConnection,
+        "SELECT id, name FROM verb WHERE name=?",
+        -1,
+        &ppStmt,
+        nullptr);
+    if (result != SQLITE_OK)
+    {
+        throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+    }
+
+    result = sqlite3_bind_text(ppStmt, 1, getName().c_str(), -1, SQLITE_STATIC);
+    switch (result)
+    {
+        case SQLITE_OK :
+            break;
+        case SQLITE_TOOBIG :
+            throw obelisk::DatabaseException::SizeException();
+            break;
+        case SQLITE_RANGE :
+            throw obelisk::DatabaseException::RangeException();
+            break;
+        case SQLITE_NOMEM :
+            throw obelisk::DatabaseException::MemoryException();
+            break;
+        default :
+            throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+            break;
+    }
+
+    result = sqlite3_step(ppStmt);
+    switch (result)
+    {
+        case SQLITE_DONE :
+            // no rows in the database
+            break;
+        case SQLITE_ROW :
+            setId(sqlite3_column_int(ppStmt, 0));
+            setName((char*) sqlite3_column_text(ppStmt, 1));
+            break;
+        case SQLITE_BUSY :
+            throw obelisk::DatabaseException::BusyException();
+            break;
+        case SQLITE_MISUSE :
+            throw obelisk::DatabaseException::MisuseException();
+            break;
+        default :
+            throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+            break;
+    }
+
+    result = sqlite3_finalize(ppStmt);
+    if (result != SQLITE_OK)
+    {
+        throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+    }
+}
+
+void obelisk::Verb::insertVerb(sqlite3* dbConnection)
+{
+    if (dbConnection == nullptr)
+    {
+        throw obelisk::DatabaseException("database isn't open");
+    }
+
+    sqlite3_stmt* ppStmt = nullptr;
+
+    auto result = sqlite3_prepare_v2(dbConnection,
+        "INSERT INTO verb (name) VALUES (?)",
+        -1,
+        &ppStmt,
+        nullptr);
+    if (result != SQLITE_OK)
+    {
+        throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+    }
+
+    result
+        = sqlite3_bind_text(ppStmt, 1, getName().c_str(), -1, SQLITE_TRANSIENT);
+    switch (result)
+    {
+        case SQLITE_OK :
+            break;
+        case SQLITE_TOOBIG :
+            throw obelisk::DatabaseException::SizeException();
+            break;
+        case SQLITE_RANGE :
+            throw obelisk::DatabaseException::RangeException();
+            break;
+        case SQLITE_NOMEM :
+            throw obelisk::DatabaseException::MemoryException();
+            break;
+        default :
+            throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+            break;
+    }
+
+    result = sqlite3_step(ppStmt);
+    switch (result)
+    {
+        case SQLITE_DONE :
+            setId((int) sqlite3_last_insert_rowid(dbConnection));
+            sqlite3_set_last_insert_rowid(dbConnection, 0);
+            break;
+        case SQLITE_CONSTRAINT :
+            throw obelisk::DatabaseException::ConstraintException(
+                sqlite3_errmsg(dbConnection));
+        case SQLITE_BUSY :
+            throw obelisk::DatabaseException::BusyException();
+            break;
+        case SQLITE_MISUSE :
+            throw obelisk::DatabaseException::MisuseException();
+            break;
+        default :
+            throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+            break;
+    }
+
+    result = sqlite3_finalize(ppStmt);
+    if (result != SQLITE_OK)
+    {
+        throw obelisk::DatabaseException(sqlite3_errmsg(dbConnection));
+    }
+}
+
+int& obelisk::Verb::getId()
 {
     return id_;
 }
@@ -21,7 +157,7 @@ void obelisk::Verb::setId(int id)
     id_ = id;
 }
 
-std::string obelisk::Verb::getName()
+std::string& obelisk::Verb::getName()
 {
     return name_;
 }

src/models/verb.h

@@ -1,6 +1,8 @@
 #ifndef OBELISK_MODELS_VERB_H
 #define OBELISK_MODELS_VERB_H
 
+#include <sqlite3.h>
+
 #include <string>
 
 namespace obelisk
@@ -38,11 +40,14 @@ namespace obelisk
 
             static const char* createTable();
 
-            int getId();
+            int& getId();
             void setId(int id);
 
-            std::string getName();
+            std::string& getName();
             void setName(std::string name);
+
+            void selectVerb(sqlite3* dbConnection);
+            void insertVerb(sqlite3* dbConnection);
     };
 } // namespace obelisk
 

src/obelisk.cpp

@@ -8,9 +8,21 @@
 #include <limits>
 #include <memory>
 
-static void mainLoop()
+static int mainLoop()
 {
     auto parser = std::unique_ptr<obelisk::Parser> {new obelisk::Parser()};
+    std::unique_ptr<obelisk::KnowledgeBase> kb;
+
+    try
+    {
+        kb = std::unique_ptr<obelisk::KnowledgeBase> {
+            new obelisk::KnowledgeBase("cromer.kb")};
+    }
+    catch (obelisk::KnowledgeBaseException& exception)
+    {
+        std::cout << exception.what() << std::endl;
+        return EXIT_FAILURE;
+    }
 
     // Prime the first token.
     fprintf(stderr, "ready> ");
@@ -22,7 +34,7 @@ static void mainLoop()
         switch (parser->getCurrentToken())
         {
             case obelisk::Lexer::kTokenEof :
-                return;
+                return EXIT_SUCCESS;
             case ';' : // ignore top-level semicolons.
                 std::cout << "Identifier: "
                           << parser->getLexer()->getIdentifier() << std::endl;
@@ -31,19 +43,21 @@ static void mainLoop()
                 parser->getNextToken();
                 break;
             case obelisk::Lexer::kTokenFact :
-                // parser->handleFactFunction();
+                parser->handleFact(kb);
                 break;
             case obelisk::Lexer::kTokenRule :
-                // parser->handleRuleFunction();
+                // parser->handleRule();
                 break;
             case obelisk::Lexer::kTokenAction :
-                // parser->handleActionFunction();
+                // parser->handleAction();
                 break;
             default :
                 parser->getNextToken();
                 break;
         }
     }
+
+    return EXIT_SUCCESS;
 }
 
 int main(int argc, char** argv)
@@ -79,28 +93,5 @@ int main(int argc, char** argv)
         return EXIT_FAILURE;
     }*/
 
-    try
+    return mainLoop();
-    {
-        auto kb = std::unique_ptr<obelisk::KnowledgeBase> {
-            new obelisk::KnowledgeBase("cromer.kb")};
-
-        /*std::vector<std::string> leftObjects;
-        std::vector<std::string> rightObjects;
-        leftObjects.push_back("chris");
-        leftObjects.push_back("martin");
-
-        rightObjects.push_back("happy");
-        rightObjects.push_back("smart");
-
-        kb->addFacts("is", leftObjects, rightObjects);*/
-    }
-    catch (obelisk::KnowledgeBaseException& exception)
-    {
-        std::cout << exception.what() << std::endl;
-        return EXIT_FAILURE;
-    }
-
-    mainLoop();
-
-    return EXIT_SUCCESS;
 }

src/obelisk.h

@@ -1 +1 @@
-static void mainLoop();
+static int mainLoop();

src/parser.cpp

@@ -1,10 +1,14 @@
 #include "ast/call_expression_ast.h"
 #include "ast/number_expression_ast.h"
 #include "ast/variable_expression_ast.h"
+#include "models/entity.h"
+#include "models/fact.h"
+#include "models/verb.h"
 #include "parser.h"
 
 #include <memory>
 #include <stack>
+#include <string>
 #include <vector>
 
 obelisk::Parser::Parser()
@@ -211,64 +215,27 @@ std::unique_ptr<obelisk::PrototypeAST> obelisk::Parser::parseExtern()
     return parsePrototype();
 }
 
+//action("martin" is "dangerous" then "avoid" or "ignore");
 std::unique_ptr<obelisk::ExpressionAST> obelisk::Parser::parseAction()
 {
-    //action(is "dangerous" then "avoid" or "ignore");
-    getNextToken();
-    if (getCurrentToken() != '(')
-    {
-        // TODO: throw an error
-    }
 }
 
+//rule("chris" and "martin" is "happy" if "chris" plays "playstation");
 std::unique_ptr<obelisk::ExpressionAST> obelisk::Parser::parseRule()
 {
-    //rule("player" can "die" if "enemy1" is "dangerous");
-    getNextToken();
-    if (getCurrentToken() != '(')
-    {
-        // TODO: throw an error
-    }
-    while (true) //left side of Rule
-    {
-        getNextToken();
-        if (getCurrentToken() != '"')
-        {
-            //TODO: throw an error
-        }
-
-        /*if (getCurrentToken() == ')') // TODO: break if not string and not "and"
-        {
-            // TODO: save the verb
-            break;
-        }*/
-    }
-    while (true) //right side of Ruke
-    {
-        getNextToken();
-        if (getCurrentToken() != '"')
-        {
-            //TODO: throw an error
-        }
-
-        if (getCurrentToken() == ')')
-        {
-            // TODO: save the verb
-            break;
-        }
-    }
 }
 
 // fact("chris cromer" and "martin" and "Isabella" can "program" and "speak english");
 // fact("" and "martin")
-std::unique_ptr<obelisk::ExpressionAST> obelisk::Parser::parseFact()
+void obelisk::Parser::parseFact(std::vector<obelisk::Fact>& facts)
 {
     std::stack<char> syntax;
 
     getNextToken();
     if (getCurrentToken() != '(')
     {
-        // TODO: throw an error
+        throw obelisk::ParserException(
+            "expected '(' but got '" + std::to_string(getCurrentToken()) + "'");
     }
 
     syntax.push('(');
@@ -326,14 +293,29 @@ std::unique_ptr<obelisk::ExpressionAST> obelisk::Parser::parseFact()
         {
             if (getCurrentToken() == ')')
             {
-                // TODO: throw an error if verb is empty
+                // closing parenthesis found, make sure we have everything needed
-                // TODO: throw an error if rightEntities has 0 elements
+                if (verb == "")
+                {
+                    throw obelisk::ParserException("verb is empty");
+                }
+
+                if (leftEntities.size() == 0)
+                {
+                    throw obelisk::ParserException(
+                        "missing left side entities");
+                }
+
+                if (rightEntities.size() == 0)
+                {
+                    throw obelisk::ParserException(
+                        "missing right side entities");
+                }
                 break;
             }
 
             if (getCurrentToken() == '"')
             {
-                // TODO: throw and error because there is an unexpected double quote.
+                throw obelisk::ParserException("unexpected '\"'");
                 break;
             }
 
@@ -352,22 +334,97 @@ std::unique_ptr<obelisk::ExpressionAST> obelisk::Parser::parseFact()
         }
     }
 
-    return nullptr;
+    for (auto& leftEntity : leftEntities)
+    {
+        for (auto& rightEntity : rightEntities)
+        {
+            facts.push_back(obelisk::Fact(obelisk::Entity(leftEntity),
+                obelisk::Entity(rightEntity),
+                obelisk::Verb(verb)));
+        }
+    }
 }
 
-void obelisk::Parser::handleAction()
+void obelisk::Parser::handleAction(std::unique_ptr<obelisk::KnowledgeBase>& kb)
 {
 }
 
-void obelisk::Parser::handleRule()
+void obelisk::Parser::handleRule(std::unique_ptr<obelisk::KnowledgeBase>& kb)
 {
 }
 
-void obelisk::Parser::handleFact()
+void obelisk::Parser::handleFact(std::unique_ptr<obelisk::KnowledgeBase>& kb)
 {
-    parseFact();
+    std::vector<obelisk::Fact> facts;
+    parseFact(facts);
+
+    int verbId = 0;
+    for (auto& fact : facts)
+    {
+        // TODO: doesn't work after first insert
+        std::vector<obelisk::Entity> entities {fact.getLeftEntity()};
+        kb->addEntities(entities);
+        fact.setLeftEntity(entities.front());
+
+        // the id was not inserted, so check if it exists in the database
+        if (fact.getLeftEntity().getId() == 0)
+        {
+            obelisk::Entity entity = fact.getLeftEntity();
+            kb->getEntity(entity);
+            if (entity.getId() == 0)
+            {
+                // TODO: throw an error here, it was not inserted, and doesn't exist in the database
+            }
+            else
+            {
+                fact.setLeftEntity(entity);
+            }
         }
 
-void obelisk::Parser::insertFact()
+        entities = {fact.getRightEntity()};
+        kb->addEntities(entities);
+        fact.setRightEntity(entities.front());
+
+        if (fact.getRightEntity().getId() == 0)
         {
+            obelisk::Entity entity = fact.getRightEntity();
+            kb->getEntity(entity);
+            if (entity.getId() == 0)
+            {
+                // TODO: throw an error here, it was not inserted, and doesn't exist in the database
             }
+            else
+            {
+                fact.setRightEntity(entity);
+            }
+        }
+
+        if (verbId == 0)
+        {
+            std::vector<obelisk::Verb> verbs = {fact.getVerb()};
+            kb->addVerbs(verbs);
+            if (verbs.front().getId() != 0)
+            {
+                // The verb was inserted
+                fact.setVerb(verbs.front());
+                verbId = fact.getVerb().getId();
+            }
+            else
+            {
+                // The verb is already already in the knowledge base
+                // TODO: SELECT the verb and save it into verbId
+            }
+        }
+        else
+        {
+            fact.getVerb().setId(verbId);
+        }
+
+        // INSERT INTO fact
+        std::vector<obelisk::Fact> facts {fact};
+        kb->addFacts(facts);
+        fact = facts.front();
+    }
+}
+
+// fact("chris cromer" and "martin" and "Isabella" can "program" and "speak english");

src/parser.h

@@ -4,7 +4,9 @@
 #include "ast/expression_ast.h"
 #include "ast/function_ast.h"
 #include "ast/prototype_ast.h"
+#include "knowledge_base.h"
 #include "lexer.h"
+#include "models/fact.h"
 
 #include <memory>
 
@@ -34,7 +36,7 @@ namespace obelisk
             std::unique_ptr<obelisk::PrototypeAST> parseExtern();
             std::unique_ptr<obelisk::ExpressionAST> parseAction();
             std::unique_ptr<obelisk::ExpressionAST> parseRule();
-            std::unique_ptr<obelisk::ExpressionAST> parseFact();
+            void parseFact(std::vector<obelisk::Fact>& facts);
 
         public:
             Parser();
@@ -48,9 +50,31 @@ namespace obelisk
             void handleDefinition();
             void handleExtern();
             void handleTopLevelExpression();
-            void handleAction();
+            void handleAction(std::unique_ptr<obelisk::KnowledgeBase>& kb);
-            void handleRule();
+            void handleRule(std::unique_ptr<obelisk::KnowledgeBase>& kb);
-            void handleFact();
+            void handleFact(std::unique_ptr<obelisk::KnowledgeBase>& kb);
+    };
+
+    class ParserException : public std::exception
+    {
+        private:
+            const std::string errorMessage_;
+
+        public:
+            ParserException() :
+                errorMessage_("an unknown error ocurred")
+            {
+            }
+
+            ParserException(const std::string& errorMessage) :
+                errorMessage_(errorMessage)
+            {
+            }
+
+            const char* what() const noexcept
+            {
+                return errorMessage_.c_str();
+            }
     };
 } // namespace obelisk