Adding a Statement::exec() method to execute a one-step query with no expected result

- similar to Database::exec(), but to be used with a SQLite prepared statement, for improved performances

src/SQLiteC++/Database.cpp

@@ -47,7 +47,7 @@ int Database::exec(const char* apQueries) // throw(SQLite::Exception);
     int ret = sqlite3_exec(mpSQLite, apQueries, NULL, NULL, NULL);
     check(ret);
 
-    // Return the number of changes made by those SQL statements
+    // Return the number of rows modified by those SQL statements (INSERT, UPDATE or DELETE)
     return sqlite3_changes(mpSQLite);
 }
 

src/SQLiteC++/Database.h

@@ -62,11 +62,12 @@ public:
      *  - Data Manipulation Language (DML) statements "INSERT", "UPDATE" and "DELETE"
      *  - Data Control Language (DCL) statements "GRANT", "REVOKE", "COMMIT" and "ROLLBACK"
      *
-     * @see Statement class and Statement::executeStep() for handling "SELECT" queries with results
+     * @see Statement::exec() to handle precompiled statements (for better performances) without results
+     * @see Statement::executeStep() to handle "SELECT" queries with results
      *
      * @param[in] apQueries  one or multiple UTF-8 encoded, semicolon-separate SQL statements
      *
-     * @return number of changes made by those SQL statements
+     * @return number of rows modified by those SQL statements (INSERT, UPDATE or DELETE)
      *
      * @throw SQLite::Exception in case of error
      */

src/SQLiteC++/Statement.cpp

@@ -163,17 +163,19 @@ bool Statement::executeStep(void) // throw(SQLite::Exception)
     if (false == mbDone)
     {
         int ret = sqlite3_step(mpStmt);
-        if (SQLITE_ROW == ret)
+        if (SQLITE_ROW == ret) // one row is ready : call getColumn(N) to access it
         {
             mbOk = true;
         }
-        else if (SQLITE_DONE == ret)
+        else if (SQLITE_DONE == ret) // no (more) row ready : the query has finished executing
         {
             mbOk = false;
             mbDone = true;
         }
         else
         {
+            mbOk = false;
+            mbDone = false;
             throw SQLite::Exception(sqlite3_errmsg(mpSQLite));
         }
     }
@@ -182,7 +184,40 @@ bool Statement::executeStep(void) // throw(SQLite::Exception)
         throw SQLite::Exception("Statement need to be reseted");
     }
 
-    return mbOk;
+    return mbOk; // true only if one row is accessible by getColumn(N)
+}
+
+// Execute a one-step query with no expected result
+int Statement::exec(void) // throw(SQLite::Exception)
+{
+    if (false == mbDone)
+    {
+        int ret = sqlite3_step(mpStmt);
+        if (SQLITE_DONE == ret) // the statement has finished executing successfully
+        {
+            mbOk = false;
+            mbDone = true;
+        }
+        else if (SQLITE_ROW == ret)
+        {
+            mbOk = false;
+            mbDone = false;
+            throw SQLite::Exception("exec() does not expect results");
+        }
+        else
+        {
+            mbOk = false;
+            mbDone = false;
+            throw SQLite::Exception(sqlite3_errmsg(mpSQLite));
+        }
+    }
+    else
+    {
+        throw SQLite::Exception("Statement need to be reseted");
+    }
+
+    // Return the number of rows modified by those SQL statements (INSERT, UPDATE or DELETE)
+    return sqlite3_changes(mpSQLite);
 }
 
 // Return a copy of the column data specified by its index starting at 0

src/SQLiteC++/Statement.h

@@ -112,8 +112,9 @@ public:
     ////////////////////////////////////////////////////////////////////////////
 
     /**
-     * @brief Execute a step of the query to fetch one row of results.
+     * @brief Execute a step of the prepared query to fetch one row of results.
      *
+     * @see exec() execute a one-step prepared statement with no expected result
      * @see Database::exec() is a shortcut to execute one or multiple statements without results
      *
      * @return - true  (SQLITE_ROW)  if there is another row ready : you can call getColumn(N) to get it
@@ -125,6 +126,22 @@ public:
      */
     bool executeStep(void); // throw(SQLite::Exception);
 
+    /**
+     * @brief Execute a one-step query with no expected result.
+     *
+     *  This exec() method is to use with precompiled statement that does not fetch results (INSERT, UPDATE, DELETE...).
+     * It is intended for similar usage as Database::exec(), but is able to reuse the precompiled underlying SQLite statement
+     * for better performances.
+     *
+     * @see executeStep() execute a step of the prepared query to fetch one row of results
+     * @see Database::exec() is a shortcut to execute one or multiple statements without results
+     *
+     * @return number of row modified by this SQL statement (INSERT, UPDATE or DELETE)
+     *
+     * @throw SQLite::Exception in case of error, or if row of results are returned !
+     */
+    int exec(void); // throw(SQLite::Exception);
+
     ////////////////////////////////////////////////////////////////////////////
 
     /**