/// <summary>
/// Initializes a new instance of the
/// <see cref="Radischevo.Wahha.Data.DbCommandResult"/> class.
/// </summary>
/// <param name="provider">The <see cref="Radischevo.Wahha.Data.IDbDataProvider"/>
/// instance used to access the database.</param>
/// <param name="command">The <see cref="Radischevo.Wahha.Data.DbCommandDescriptor"/>
/// describing the command to execute.</param>
public DbCommandResult(IDbDataProvider provider, DbCommandDescriptor command)
{
Precondition.Require(provider, () => Error.ArgumentNull("provider"));
_provider = provider;
_command = command;
_behavior = CommandBehavior.Default;
}
/// <summary>
/// Executes the operation against the provided data source
/// and returns the result.
/// </summary>
/// <param name="context">Provides the current operation context.</param>
protected override TResult ExecuteInternal(DbOperationContext context)
{
DbCommandDescriptor command = CreateCommand();
Precondition.Require(command, () => Error.CommandIsNotInitialized());
return(ExecuteCommand(context, command));
}
/// <summary>
/// Executes the provided <paramref name="command"/>
/// against the provided data source and returns the result.
/// </summary>
/// <param name="context">Provides the current operation context.</param>
/// <param name="command">The command instance to execute.</param>
protected override TEntity ExecuteCommand(DbOperationContext context,
DbCommandDescriptor command)
{
return(context.Provider.Execute(command).AsDataReader <TEntity>(reader => {
if (reader.Read())
{
return Materializer.Materialize(reader);
}
return default(TEntity);
}));
}
/// <summary>
/// Executes the operation against the provided data source
/// and returns the result.
/// </summary>
/// <param name="context">Provides the current operation context.</param>
protected override TResult ExecuteInternal(DbOperationContext context)
{
DbCommandDescriptor command = CreateCommand();
Precondition.Require(command, () => Error.CommandIsNotInitialized());
string cacheKey = CreateCacheKey(command);
return(context.Cache.Get <TResult>(cacheKey,
() => ExecuteCommand(context, command),
DateTime.Now.Add(_expirationTimeout),
Tags));
}
/// <summary>
/// Executes the provided <paramref name="command"/>
/// against the provided data source and returns the result.
/// </summary>
/// <param name="context">Provides the current operation context.</param>
/// <param name="command">The command instance to execute.</param>
protected override IEnumerable <TEntity> ExecuteCommand(DbOperationContext context,
DbCommandDescriptor command)
{
return(context.Provider.Execute(command).AsDataReader(reader => {
List <TEntity> collection = new List <TEntity>(BufferSize);
while (reader.Read())
{
collection.Add(Materializer.Materialize(reader));
}
return collection;
}));
}
/// <summary>
/// Executes the provided <paramref name="command"/>
/// against the provided data source and returns the result.
/// </summary>
/// <param name="context">Provides the current operation context.</param>
/// <param name="command">The command instance to execute.</param>
protected override IEnumerable <TEntity> ExecuteCommand(DbOperationContext context,
DbCommandDescriptor command)
{
return(context.Provider.Execute(command).AsDataReader(reader => {
List <TEntity> collection = new List <TEntity>(BufferSize);
int count = 0;
while (reader.Read())
{
collection.Add(Materializer.Materialize(reader));
}
if (reader.NextResult() && reader.Read())
{
count = reader.GetValue <int>(0);
}
return collection.ToSubset(count);
}));
}
/// <summary>
/// Creates the unique cache key based on the text representation
/// of the provided command and its parameters values.
/// </summary>
/// <param name="command">The command to create fingerprint from.</param>
protected virtual string CreateCacheKey(DbCommandDescriptor command)
{
StringBuilder sb = new StringBuilder();
MD5 md5 = MD5.Create();
Encoding encoding = Encoding.UTF8;
sb.Append(GetType().FullName).Append("::")
.Append(command.Text).Append("::")
.Append(command.Type.ToString());
sb.Append("=>{");
foreach (DbParameterDescriptor parameter in command.Parameters)
{
sb.Append("[").Append(parameter.Name).Append("=")
.Append((parameter.Value == DBNull.Value) ? "<NULL>" :
Convert.ToString(parameter.Value, CultureInfo.InvariantCulture))
.Append("]");
}
sb.Append("}");
return(Converter.ToBase16String(md5.ComputeHash(encoding.GetBytes(sb.ToString()))));
}
/// <summary>
/// Creates a <see cref="Radischevo.Wahha.Data.DbCommandResult"/> wrapper for
/// the specified <paramref name="command"/>.
/// </summary>
/// <param name="provider">An instance of data provider being extended.</param>
/// <param name="command">The object, describing the command to execute.</param>
public static DbCommandResult Execute(this IDbDataProvider provider, DbCommandDescriptor command)
{
Precondition.Require(provider, () => Error.ArgumentNull("provider"));
return(new DbCommandResult(provider, command));
}
/// <summary>
/// Creates a <see cref="Radischevo.Wahha.Data.DbCommandResult"/> wrapper for
/// the specified <paramref name="command"/>.
/// </summary>
/// <param name="provider">An instance of data provider being extended.</param>
/// <param name="command">The object, describing the command to execute.</param>
public static DbCommandResult Execute(this IDbDataProvider provider, DbCommandDescriptor command)
{
Precondition.Require(provider, () => Error.ArgumentNull("provider"));
return new DbCommandResult(provider, command);
}
/// <summary>
/// Executes the operation against the provided data source
/// and returns a number of rows affected.
/// </summary>
/// <param name="context">Provides the current operation context.</param>
/// <param name="command">The command instance to execute.</param>
protected override int ExecuteCommand(DbOperationContext context,
DbCommandDescriptor command)
{
return(context.Provider.Execute(command).AsNonQuery());
}
/// <summary> /// When overridden in a derived class, executes the provided <paramref name="command"/> /// against the provided data source and returns the result. /// </summary> /// <param name="context">Provides the current operation context.</param> /// <param name="command">The command instance to execute.</param> protected abstract TResult ExecuteCommand(DbOperationContext context, DbCommandDescriptor command);
/// <summary>
/// Executes the operation against the provided data source
/// and returns the scalar result.
/// </summary>
/// <param name="context">Provides the current operation context.</param>
/// <param name="command">The command instance to execute.</param>
protected override TResult ExecuteCommand(DbOperationContext context,
DbCommandDescriptor command)
{
return(context.Provider.Execute(command).AsScalar <TResult>());
}
