private static bool Exists(this OracleConnection connection, DbName objectName)
{
using (var command = connection.CreateCommand())
{
if (objectName.Owner == null)
{
command.CommandText = "select 1 from user_objects where object_name = upper(:name)";
command.Parameters.Add("name", objectName.Name);
}
else
{
command.CommandText = "select 1 from all_objects where owner = upper(:owner) and object_name = upper(:name)";
command.Parameters.Add("owner", objectName.Owner);
command.Parameters.Add("name", objectName.Name);
}
return(command.ExecuteScalar() != null);
}
}
private static bool CreateIfNotExists(this OracleConnection connection, DbName tableName, Func <DbName, string[]> ddl)
{
if (connection == null)
{
throw new ArgumentNullException(nameof(connection));
}
if (connection.Exists(tableName))
{
return(false);
}
try
{
using (var command = connection.CreateCommand())
{
foreach (var sql in ddl(tableName))
{
command.CommandText = sql;
command.ExecuteNonQuery();
}
}
}
catch
{
// We might fail if another process created the same objects concurrently
if (connection.Exists(tableName))
{
return(false);
}
// Otherwise propagate the error
throw;
}
return(true);
}
/// <summary>Create objects supporting DataBus.</summary> public static bool CreateRebusDataBus(this OracleConnection connection, DbName tableName) => connection.CreateIfNotExists(tableName, DDL.dataBus);
/// <summary>Create objects supporting Sagas Snapshots.</summary> public static bool CreateRebusSagaSnapshot(this OracleConnection connection, DbName tableName) => connection.CreateIfNotExists(tableName, DDL.sagaSnapshot);
/// <summary>Create objects supporting Sagas.</summary>
public static bool CreateRebusSaga(this OracleConnection connection, DbName dataTableName, DbName indexTableName)
{
return(connection.CreateIfNotExists(dataTableName, DDL.sagaData) |
connection.CreateIfNotExists(indexTableName, DDL.sagaIndex));
}
/// <summary>Create objects supporting Subscriptions.</summary> public static bool CreateRebusSubscription(this OracleConnection connection, DbName tableName) => connection.CreateIfNotExists(tableName, DDL.subscription);
/// <summary>Create objects supporting Timeouts.</summary> public static bool CreateRebusTimeout(this OracleConnection connection, DbName tableName) => connection.CreateIfNotExists(tableName, DDL.timeout);