# SDO_DAS_Relational::__construct

(No version information available, might be only in CVS)

SDO_DAS_Relational::__construct — Creates an instance of a Relational Data Access Service

### Description

SDO_DAS_Relational SDO_DAS_Relational::__construct ( array `$database_metadata` [, string `$application_root_type` [, array `$SDO_containment_references_metadata` ]] )
Warning

This function is EXPERIMENTAL. The behaviour of this function, the name of this function, and anything else documented about this function may change without notice in a future release of PHP. Use this function at your own risk.

Constructs an instance of a Relational Data Access Service from the passed metadata.

### Parameters

database_metadata

  An array containing one or more table definitions, each of which is an associative array containing the keys name, columns, PK, and optionally, FK. For a full discussion of the metadata, see the metadata section in the general information about the Relational DAS.

application_root_type

  The root of each data graph is an object of a special root type and the application data objects come below that. Of the various application types in the SDO model, one has to be the the application type immediately below the root of the data graph. If there is only one table in the database metadata, so the application root type can be inferred, this argument can be omitted.

SDO_containment_references_metadata

  An array containing one or more definitions of a containment relation, each of which is an associative array containing the keys parent and child. The containment relations describe how the types in the model are connected to form a tree. The type specified as the application root type must be present as one of the parent types in the containment references. If the application only needs to work with one table at a time, and there are no containment relations in the model, this argument can be omitted. For a full discussion of the metadata, see the metadata section in the general information about the Relational DAS.

### Return Values

Returns an SDO_DAS_Relational object on success.

### Errors/Exceptions

SDO_DAS_Relational::__construct() throws a SDO_DAS_Relational_Exception if any problems are found in the metadata.

### Examples

For a full discussion of the metadata, see the metadata section in the general information about the Relational DAS.