Tables, views, and synonyms overview

Databases provide the common database objects that include tables, views, and synonyms.

Table is a common database schema object in a database. The table objects are used to store data in the database. Databases such as DB2®, Oracle, and SQL Server provide a number of table types such as object, normal, nested, clustered, index-organized, for entering data into the database.

View is a database object that is considered as a virtual table or a stored query. Views do not store the data physically in them; instead they derive the data from the base table on which they are created. All the operations that are performed on the tables can be performed on views too.

Synonym is an alias or an alternative name given for the database objects such as the tables, views, and other database objects.

Wrapper business objects

A wrapper business object enables you to manipulate unrelated table and view business objects in a single operation. The wrapper business object contains simple attributes for the primary keys of each child business object. The name of the field is the string "wrap", followed by the database table name and the column name of the primary key of the table. The wrapper business object also contains a complex attribute for each table business object. The name of the attribute is the table name appended with the string "obj". The type of the complex attribute is the name of the corresponding table business object.

In the following example, the wrapper business object generated WrapperBO contains three child business objects. Db2adminCustomer that has a primary key (pkey), Db2adminCustInfo that has a primary key (ccode), and Db2adminCustomer_Compositekey that has a composite primary key (fname, lname). The following sections describe how to execute the Create, Update, Delete, and Retrieve operations on this wrapper business object.

Figure 1. Wrapper business object

You can create wrapper business objects in the Specify Composite Properties window of the external service wizard. For information about how to create wrapper business objects, see Setting global properties for operations and creating wrapper business objects. The wrapper business objects support the Create, Retrieve, Update, and Delete operations. The behavior of each operation is explained in the table below.

Table 1. Behavior of operations on wrapper business objects

Operation	Action
	When you set a value of a wrapper business object and there are no corresponding child business instances of the key	When you set the value of a key in wrapper business object, and add a child business object instance: If the primary key of the child business object instance is not set, the primary key value of the child business object instance is copied from the corresponding key in the wrapper business object and is used to execute the operation. If the primary key of the child business object is If the child business object instances primary key value is set and different from the corresponding key value in the wrapper business object, then the key value in wrapper business object is ignored and the key value of the child business object is used to execute the operation.
Create	The Create operation is executed successfully and the returned child business objects are empty. No record is inserted in the database.	If the record of the child business object instance does not exist in the database, the record is inserted into database. If the record of the child business object instance exists in the database, the adapter returns the UniqueConstraintViolatedException.
Retrieve	If the key is valid, the corresponding record of the key is returned. If the keys are invalid, no record is returned.	If the record of the child business object instance exists in the database, the record is returned. If the record of the child business object instance is not found in the database, the adapter returns the RecordNotFoundException.
Update	The Update operation is executed successfully. No record is updated in the database.	If any child business object does not exist, the record is inserted into the database. If the child business object exists, the record is updated in the database. If the primary key for any child business object is unset, the record is updated with the key value copied from the corresponding key in the wrapper business object.
Delete	The Delete operation is executed successfully if the key is valid, and the corresponding child business object is deleted.	Only the specified child business object is deleted. If the primary key for any child business object is unset, the record with the wrapper business object key value is deleted. If any child business object does not exist in the database, the adapter returns the RecordNotFoundException.