/// <summary>
/// Checks whether the target column is an identity field from the database.
/// </summary>
/// <typeparam name="TEntity"></typeparam>
/// <param name="connectionString">The connection string object to be used.</param>
/// <param name="command">The target command.</param>
/// <param name="columnName">The name of the column.</param>
/// <returns>A boolean value indicating the identification of the column.</returns>
public static bool IsIdentity <TEntity>(string connectionString, Command command, string columnName)
where TEntity : class
{
var isIdentity = false;
// Open a connection
using (var connection = new SqlConnection(connectionString).EnsureOpen())
{
var commandType = CommandTypeCache.Get <TEntity>(command);
// Check for the command type
if (commandType != CommandType.StoredProcedure)
{
var mappedName = ClassMappedNameCache.Get <TEntity>(command);
var commandText = @"
SELECT CONVERT(INT, c.is_identity) AS IsIdentity
FROM [sys].[columns] c
INNER JOIN [sys].[objects] o ON o.object_id = c.object_id
WHERE (c.[name] = @ColumnName)
AND (o.[name] = @TableName)
AND (o.[type] = 'U');" ;
// Open a command
using (var dbCommand = connection.EnsureOpen().CreateCommand(commandText))
{
// Create parameters
dbCommand.CreateParameters(new
{
ColumnName = columnName.AsUnquoted(),
TableName = mappedName.AsUnquoted()
});
// Execute and set the result
var result = dbCommand.ExecuteScalar();
if (result != null && result != DBNull.Value)
{
isIdentity = Convert.ToBoolean(result);
}
}
}
}
// Return the value
return(isIdentity);
}
/// <summary>
/// Gets the cached field definitions of the entity.
/// </summary>
/// <typeparam name="TEntity">The type of the target entity.</typeparam>
/// <param name="command">The target command</param>
/// <param name="connectionString">The connection string to be used.</param>
/// <returns>The cached field definitions of the entity.</returns>
public static IEnumerable <FieldDefinition> Get <TEntity>(Command command, string connectionString)
where TEntity : class
{
var key = $"{typeof(TEntity).FullName}.{command.ToString()}";
var result = (IEnumerable <FieldDefinition>)null;
if (m_cache.TryGetValue(key, out result) == false)
{
var commandType = CommandTypeCache.Get <TEntity>(command);
if (commandType != CommandType.StoredProcedure)
{
var tableName = ClassMappedNameCache.Get <TEntity>(command);
result = SqlDbHelper.GetFieldDefinitions(connectionString, tableName);
}
m_cache.TryAdd(key, result);
}
return(result);
}
