Пример #1
0
        /// --------------------------------------------------------------------------------
        /// <summary>
        /// Extracts the fields to save to the database from the objItem.SaveFields function.
        /// The fields are then written to the database using either an SQL INSERT or UPDATE
        /// depending on whether the object has already been saved. If the collection has
        /// implemented IDatabaseObjects.KeyFieldName then objItem's key is also validated to
        /// ensure it is not null and unique within the collection. If objCollection has
        /// implemented IDatabaseObjects.Subset then objItem should exist within objCollection.
        /// If not, a duplicate key error may occur if the obItem's key is being used in
        /// another subset in the same table. If a record is being amended
        /// (IDatabaseObject.IsSaved returns true) then the function will "AND" the collection's
        /// IDatabaseObjects.Subset conditions and the objItem's IDatabaseObject.DistinctValue
        /// value to create the WHERE clause in the UPDATE statement. Therefore, the
        /// combination of the IDatabaseObjects.Subset and IDatabaseObject.DistinctValue
        /// conditions MUST identify only one record in the table. Otherwise multiple records
        /// will be updated with the same data. If data is only inserted and not amended
        /// (usually a rare occurance) then this requirement is unnecessary.
        /// </summary>
        ///
        /// <param name="objCollection">
        /// The collection which contains or will contain the object to save.
        /// </param>
        ///
        /// <param name="objItem">
        /// The object to save to the database. The values saved to the database are extracted from the
        /// SQLFieldValues object returned from IDatabaseObject.SaveFields.
        /// </param>
        ///
        /// <example> Saves a product object (Me) to the database.
        /// <code>
        /// Public Sub Save()
        ///
        ///     objDatabase.ObjectSave(NorthwindDB.Products, Me)
        ///
        /// End Sub
        /// </code>
        /// </example>
        /// --------------------------------------------------------------------------------
        ///
        public void ObjectSave(IDatabaseObjects objCollection, IDatabaseObject objItem)
        {
            SQL.SQLFieldValues objFieldValues;
            var objNewGUID = Guid.Empty;
            var autoAssignment = MergeDistinctFieldAutoAssignmentAndDistinctFieldAutoIncrements(objCollection);

            objFieldValues = objItem.SaveFields();

            if (objFieldValues == null)
                throw new Exceptions.DatabaseObjectsException(objItem.GetType().Name + " IDatabaseObject.SaveFields not implemented");

            //Add the distinct field value if it hasn't been added via the SaveFields sub
            if (!objFieldValues.Exists(objCollection.DistinctFieldName()))
            {
                if (autoAssignment == SQL.FieldValueAutoAssignmentType.None)
                    objFieldValues.Add(objCollection.DistinctFieldName(), objItem.DistinctValue);
                else if (autoAssignment == SQL.FieldValueAutoAssignmentType.NewUniqueIdentifier)
                {
                    //For a new object, with a GUID that should be automatically assigned
                    //Create a new GUID for the distinct field so that it saved for the INSERT
                    if (!objItem.IsSaved)
                    {
                        objNewGUID = System.Guid.NewGuid();
                        objFieldValues.Add(objCollection.DistinctFieldName(), objNewGUID);
                    }
                }
            }

            #if !DEBUG
            ItemKeyEnsureValid(objCollection, objItem, objFieldValues);
            #endif

            using (ConnectionScope objConnection = new ConnectionScope(this))
            {

                if (objItem.IsSaved)
                {
                    var objUpdate = new SQL.SQLUpdate();
                    objUpdate.TableName = objCollection.TableName();
                    objUpdate.Fields.Add(objFieldValues);
                    objUpdate.Where.Add(objCollection.DistinctFieldName(), SQL.ComparisonOperator.EqualTo, objItem.DistinctValue);
                    var objSubset = objCollection.Subset();
                    if (objSubset != null && !objSubset.IsEmpty)
                    {
                        objUpdate.Where.Add(objSubset);
                    }

                    if (objConnection.ExecuteNonQuery(objUpdate) != 1)
                        throw new Exceptions.RecordDoesNotExistException(objCollection, objItem);
                }
                else
                {
                    var objInsert = new SQL.SQLInsert();
                    objInsert.TableName = objCollection.TableName();
                    objInsert.Fields = objFieldValues;
                    objConnection.ExecuteNonQuery(objInsert);

                    if (autoAssignment == SQL.FieldValueAutoAssignmentType.NewUniqueIdentifier)
                        objItem.DistinctValue = objNewGUID;
                    else if (autoAssignment == SQL.FieldValueAutoAssignmentType.AutoIncrement)
                        objItem.DistinctValue = objConnection.ExecuteScalar(new SQL.SQLAutoIncrementValue());

                    object objRollbackDistinctValue = objItem.DistinctValue;
                    objItem.IsSaved = true;

                    if (Transaction.Current != null)
                    {
                        Transaction.Current.EnlistVolatile(new TransactionExecuteActionOnRollback(() => objItem.IsSaved = false), EnlistmentOptions.None);
                        Transaction.Current.EnlistVolatile(new TransactionExecuteActionOnRollback(() => objItem.DistinctValue = objRollbackDistinctValue), EnlistmentOptions.None);
                    }
                }
            }
        }
Пример #2
0
        /// --------------------------------------------------------------------------------
        /// <summary>
        /// Sets the field value for the database record associated with the object and
        /// collection.
        /// </summary>
        /// <param name="objCollection">
        /// The collection that the object exists within.
        /// The function utilises the collection's subset and tablename to determine which
        /// table and record to modify.
        /// </param>
        /// <param name="objItem">
        /// The object which represents the database record to be set. Specifically,
        /// the object's distinct field name is used to determine which record to modify.
        /// </param>
        /// <param name="strFieldName">
        /// The name of the database field that is to be set.
        /// </param>
        /// <param name="objNewValue">
        /// The new value that the database field it to be set to.
        /// If Nothing/null then the field is set to NULL.
        /// </param>
        /// <exception cref="Exceptions.ObjectDoesNotExistException">If the object has not already been saved</exception>
        /// --------------------------------------------------------------------------------
        public void ObjectSetFieldValue(IDatabaseObjects objCollection, IDatabaseObject objItem, string strFieldName, object objNewValue)
        {
            if (!objItem.IsSaved)
                throw new Exceptions.ObjectDoesNotExistException(objItem);

            SQL.SQLUpdate objUpdate = new SQL.SQLUpdate();
            objUpdate.TableName = objCollection.TableName();
            objUpdate.Fields.Add(strFieldName, objNewValue);
            objUpdate.Where.Add(objCollection.DistinctFieldName(), SQL.ComparisonOperator.EqualTo, objItem.DistinctValue);

            var objSubset = objCollection.Subset();
            if (objSubset != null && !objSubset.IsEmpty)
                objUpdate.Where.Add(objSubset);

            using (ConnectionScope objConnection = new ConnectionScope(this))
                objConnection.ExecuteNonQuery(objUpdate);
        }