/// <summary>
/// Handles decoding an instance from a query result
/// </summary>
/// <param name="queryResult">The query result to decode</param>
/// <returns>The item decoded from the query result</returns>
private T __Decode(IQueryResult queryResult)
{
// Make the result
T result = new T();
// Iterate over all properties
for (int index = 0; index < myModelProperties.Length; index++)
{
// get a nice shorthand reference
PropertyInfo pi = myModelProperties[index];
// Get the DataField attribute
DataField field = pi.GetCustomAttribute <DataField>();
// Get the value from the query result
object value = queryResult.Row[field.FieldName];
// If the value is DbNull, we need to explicitly cast the value to null
if (value.GetType() == typeof(DBNull))
{
value = null;
}
// Otherwise, we should have a value, we check to see if it is a nullable field
else if (pi.PropertyType.IsGenericType && pi.PropertyType.Name.Remove(pi.PropertyType.Name.IndexOf('`')) == "Nullable")
{
// Get the type for the property from the nullable instance's generic types
Type paramType = pi.PropertyType.GenericTypeArguments[0];
// If the value is a value type, and the given value is the same as the default value for that type,
// we assume that the field should be null
if (paramType.IsValueType && Activator.CreateInstance(paramType).Equals(value))
{
value = null;
}
// If the value is null, simply set it to null
if (value == null)
{
pi.SetValue(result, value);
}
// Otherwise
else
{
// If it is a foriegn key to another table, use the value as a primary key to get the data from the table
if (pi.GetCustomAttribute <ForeignKey>() != null)
{
pi.SetValue(result, DataAccess.FromPrimaryKeyWeak(pi.PropertyType, value));
}
// Otherwise just cast it to the properties type and set the value
else
{
pi.SetValue(result, Convert.ChangeType(value, pi.PropertyType.GenericTypeArguments[0]));
}
}
}
// Finally, for any other type
else
{
// If it is a foriegn key to another table, use the value as a primary key to get the data from the table
if (pi.GetCustomAttribute <ForeignKey>() != null)
{
pi.SetValue(result, DataAccess.FromPrimaryKeyWeak(pi.PropertyType, value));
}
// Otherwise just cast it to the properties type and set the value
else
{
pi.SetValue(result, Convert.ChangeType(value, pi.PropertyType));
}
}
}
// return the decoded result
return(result);
}
/// <summary>
/// Gets a collection of models from the database that match the fields set in the given model
/// </summary>
/// <param name="match">The model instance to match</param>
/// <returns>A collection of models from the database</returns>
public T[] GetMatches(T match)
{
// Iterate over dependancies
for (int index = 0; index < myDependencies.Length; index++)
{
// Get the value from the property
object pValue = myDependencies[index].GetValue(match);
// IF the database does not contain something that matches, we know that we cannot have this instance
if (pValue != null && !DataAccess.ExistsWeak(myDependencies[index].PropertyType, pValue))
{
return(new T[0]);
}
}
// We need to build two sides of the query, allocate strings
string searchTerms = "";
string resultValues = "";
// We also need to store a list of values to insert as well as a list of query parameters
List <object> insertParams = new List <object>();
List <QueryParam> queryParams = new List <QueryParam>();
// Iterate over each property
for (int index = 0; index < myModelProperties.Length; index++)
{
// Get the value of the property
object value = myModelProperties[index].GetValue(match);
// Get the DataField attribute
DataField dField = myModelProperties[index].GetCustomAttribute <DataField>();
// Check for a null value
if (value == null)
{
// just ignore
}
// Next see if this is a foreign key
else if (myModelProperties[index].GetCustomAttribute <ForeignKey>() != null)
{
// Use the DataAccess to get the primary key value for the instance
object key = DataAccess.GetPrimaryKeyWeak(myModelProperties[index].PropertyType, value);
// Append the the field name to the search
searchTerms += string.Format("{0}=@{0} AND ", dField.FieldName);
// Make and insert the query parameter
queryParams.Add(new QueryParam(dField.FieldName, dField.FieldType));
// Add that key value we got
insertParams.Add(key);
}
// Otherwise it is a regular data field
else if (myModelProperties[index].GetCustomAttribute <PrimaryKey>() == null)
{
// Append the the field name to the search
searchTerms += string.Format("{0}=@{0} AND ", dField.FieldName);
// Make and insert the query parameter
queryParams.Add(new QueryParam(dField.FieldName, dField.FieldType));
// Add that key value we got
insertParams.Add(value);
}
resultValues += dField.FieldName + ",";
}
// Prep the final query
string query = string.Format("select {1} from {0} where {2}", myTableName, resultValues.Trim(','), searchTerms.Remove(searchTerms.Length - 5, 4).Trim());
// Execute the query
IQueryResult result = DataAccess.Execute(query, queryParams.ToArray(), insertParams.ToArray());
T[] results = new T[result.NumRows];
for (int index = 0; index < results.Length; index++)
{
results[index] = __Decode(result);
result.MoveNext();
}
// Return true if at least one row was effected
return(results);
}
/// <summary>
/// Handles inserting a model instance into the database
/// </summary>
/// <param name="model">The model isntance to insert</param>
/// <returns>True if the insert was successful, false if otherwise</returns>
public bool Insert(T model)
{
// Iterate over dependancies
for (int index = 0; index < myDependencies.Length; index++)
{
// Get the value from the property
object pValue = myDependencies[index].GetValue(model);
if (pValue == null && myDependencies[index].GetCustomAttribute <Nullable>() == null)
{
throw new InvalidOperationException("Cannot insert with a missing dependancy");
}
// IF the database does not contain something that matches, add one
if (!DataAccess.ExistsWeak(myDependencies[index].PropertyType, pValue))
{
DataAccess.InsertWeak(myDependencies[index].PropertyType, pValue);
}
myDependencies[index].SetValue(model, DataAccess.MatchWeak(myDependencies[index].PropertyType, pValue)[0]);
}
// We need to build two sides of the query, allocate strings
string insertLeft, insertRight;
insertLeft = insertRight = "";
// We also need to store a list of values to insert as well as a list of query parameters
List <object> insertParams = new List <object>();
List <QueryParam> queryParams = new List <QueryParam>();
// Iterate over each property
for (int index = 0; index < myModelProperties.Length; index++)
{
// Get the value of the property
object value = myModelProperties[index].GetValue(model);
// Get the DataField attribute
DataField dField = myModelProperties[index].GetCustomAttribute <DataField>();
// We only include in insert if auto-generaed is false
if (myModelProperties[index].GetCustomAttribute <AutoGenerated>() == null)
{
// Check for a null value
if (value == null)
{
// If we do not allow null, throw an exception, otherwise ignore
if (myModelProperties[index].GetCustomAttribute <Nullable>() == null)
{
throw new InvalidOperationException("Cannot insert with non-nullable field not set: " + myModelProperties[index].Name);
}
}
// Next see if this is a foreign key
else if (myModelProperties[index].GetCustomAttribute <ForeignKey>() != null)
{
// Use the DataAccess to get the primary key value for the instance
object key = DataAccess.GetPrimaryKeyWeak(myModelProperties[index].PropertyType, value);
// Append the field name to the left string
insertLeft += dField.FieldName + ",";
// Append the field name as a parameter to the right string
insertRight += string.Format("@{0},", dField.FieldName);
// Make and insert the query parameter
queryParams.Add(new QueryParam(dField.FieldName, dField.FieldType));
// Add that key value we got
insertParams.Add(key);
}
// Otherwise it is a regular data field
else
{
// Append the field name to the left string
insertLeft += dField.FieldName + ",";
// Append the field name as a parameter to the right string
insertRight += string.Format("@{0},", dField.FieldName);
// Make and insert the query parameter
queryParams.Add(new QueryParam(dField.FieldName, dField.FieldType));
// Add that key value we got
insertParams.Add(value);
}
}
}
// Prep the final query
string query = string.Format("insert into {0} ({1}) VALUES ({2})", myTableName, insertLeft.Trim(','), insertRight.Trim(','));
// Execute the query
int results = DataAccess.ExecuteStatement(query, queryParams.ToArray(), insertParams.ToArray());
// Return true if at least one row was effected
return(results > 0);
}
/// <summary>
/// Handles updating a model in the database
/// </summary>
/// <param name="value">The value of the model to update</param>
/// <param name="updateNullValues">True if null values should be assigned to null in the database, false to keep existing</param>
/// <param name="updateChildren">True if referenced items should be updated, false if otherwise</param>
/// <returns>The number of rows to be modified. In most cases this should be 1</returns>
public int Update(T value, bool updateNullValues = true, bool updateChildren = true)
{
// Iterate over dependancies
if (updateChildren)
{
for (int index = 0; index < myDependencies.Length; index++)
{
// Get the value from the property
object pValue = myDependencies[index].GetValue(value);
// If the value is null and the field is not nullable
if (pValue == null && myDependencies[index].GetCustomAttribute <Nullable>() == null)
{
// if we are trying to update the nullable fields, throw an exception
if (updateNullValues)
{
throw new InvalidOperationException("Cannot insert with a missing dependancy");
}
}
else
{
// IF the database does not contain something that matches, add one
if (!DataAccess.ExistsWeak(myDependencies[index].PropertyType, pValue))
{
DataAccess.InsertWeak(myDependencies[index].PropertyType, pValue);
myDependencies[index].SetValue(value, DataAccess.MatchWeak(myDependencies[index].PropertyType, pValue)[0]);
}
else if (updateChildren)
{
DataAccess.UpdateWeak(myDependencies[index].PropertyType, pValue);
}
}
}
}
// We need to build two sides of the query, allocate strings
string updateValues, updateSearch;
updateValues = updateSearch = "";
// We also need to store a list of values to insert as well as a list of query parameters
List <object> insertParams = new List <object>();
List <QueryParam> queryParams = new List <QueryParam>();
// Iterate over each property
for (int index = 0; index < myModelProperties.Length; index++)
{
// Get the value of the property
object pValue = myModelProperties[index].GetValue(value);
// Get the DataField attribute
DataField dField = myModelProperties[index].GetCustomAttribute <DataField>();
if (myModelProperties[index].GetCustomAttribute <PrimaryKey>() != null)
{
if (myModelProperties[index].GetCustomAttribute <ForeignKey>() != null)
{
// Use the DataAccess to get the primary key value for the instance
pValue = DataAccess.GetPrimaryKeyWeak(myModelProperties[index].PropertyType, pValue);
}
if (pValue == null)
{
throw new ArgumentException("Cannot update without primary key set. Has this record been retreived from the DB?");
}
// Append the field name as a parameter to the right string
updateSearch += string.Format("{0}=@{0} AND ", dField.FieldName);
// Make and insert the query parameter
queryParams.Add(new QueryParam(dField.FieldName, dField.FieldType));
// Add that key value we got
insertParams.Add(pValue);
}
// We only include in insert if auto-generaed is false
else if (myModelProperties[index].GetCustomAttribute <AutoGenerated>() == null)
{
// Check for a null value
if (pValue == null)
{
if (updateNullValues)
{
// If we do not allow null, throw an exception, otherwise ignore
if (myModelProperties[index].GetCustomAttribute <Nullable>() == null)
{
throw new InvalidOperationException("Cannot insert with non-nullable field not set: " + myModelProperties[index].Name);
}
else
{
updateValues += string.Format("{0}=null,", dField.FieldName);
}
}
}
// Next see if this is a foreign key
else if (myModelProperties[index].GetCustomAttribute <ForeignKey>() != null)
{
// Use the DataAccess to get the primary key value for the instance
object key = DataAccess.GetPrimaryKeyWeak(myModelProperties[index].PropertyType, pValue);
// Append the field name to the left string
updateValues += string.Format("{0}=@{0},", dField.FieldName);
// Make and insert the query parameter
queryParams.Add(new QueryParam(dField.FieldName, dField.FieldType));
// Add that key value we got
insertParams.Add(key);
}
// Otherwise it is a regular data field
else
{
// Append the field name to the left string
updateValues += string.Format("{0}=@{0},", dField.FieldName);
// Make and insert the query parameter
queryParams.Add(new QueryParam(dField.FieldName, dField.FieldType));
// Add that key value we got
insertParams.Add(pValue);
}
}
}
// Prep the final query
string query = string.Format("update {0} set {1} where {2}", myTableName, updateValues.Trim(','), updateSearch.Remove(updateSearch.Length - 5, 4).Trim());
// Execute the query
int results = DataAccess.ExecuteStatement(query, queryParams.ToArray(), insertParams.ToArray());
// Return true if at least one row was effected
return(results);
}
