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TYPES - LOB HANDLE

Short Reference

Other versions: 7.31 | 7.40 | 7.54

Syntax


TYPES dtype TYPE dbtab lob_handle_type FOR lob_handle_columns 

                 
    [lob_handle_type FOR lob_handle_columns 

                 
     ...            
                      ].

Effect

Derivation of an LOB handle structure as work area for working with streaming and locators in Open SQL. For dbtab, you must specify a database table which is defined in the ABAP dictionary, or a view that is defined in the ABAP Dictionary.

The column specifications lob_handle_columns are used to determine LOBs from dbtab. The statement creates a deep structure which is constructed exactly the same for all columns which are not included in the column specification as it is for a normal TYPE reference to dbtab. For the LOBs included in the column specifications, a component with the same name is created as a LOB handle component. The static type of the LOB handle components is a class or an interface which is determined by the type specification lob_handle_type, and is assigned to the respective column specification.

The combination possibilities of the additions specified at lob_handle_columns and lob_handle_type, is determined using the following rules:

  • An LOB handle structure can be derived for either read-only, or for write-only Open SQL statements.
  • A structure for write accesses can only contain the type specifications WRITER and LOCATOR.
  • The definition of the LOB handle components must not contain contradictions, columns must not be assigned to unsuitable types or a column cannot be assigned to multiple types.
  • The definition of LOB handle components must not contain redundancies. Each specification of

    ... lob_handle_type FOR lob_handle_columns ...

    must create a set of LOB handle components which do not overlap with the LOB handle component set of another specification.
  • The definition of LOB handle components must have a minimum number of specifications. If a specification can create the same set of LOB handle components as multiple specifications, the more extensive specification must be used.

Apart from the rules listed under lob_handle_columns and lob_handle_type, there are also the following general restrictions:

  • At least one column specification must be made.
  • The type specification for the first three column specifications for LOB handle component read accesses and the first two columns for LOB handle component write accesses can not be the same.
  • In each case there can only be one column specification ALL ... COLUMNS, in which BLOB or CLOB are specified.
  • The column specifications ALL BLOB|CLOB COLUMNS include all BLOBs or CLOBs. When they are specified, you cannot also specify an individual BLOB or CLOB in a column specification COLUMNS ... for the same static type.
  • The column specification ALL OTHER COLUMNS includes all columns that are not specified individually. ALL OTHER BLOB COLUMNS and ALL OTHER CLOB COLUMNS cannot be specified at the same time.
  • The ALL COLUMNS column specification includes all LOBs and can therefore only be specified on its own.


Notes

  • LOB handle structures can also be defined using the corresponding specification of components between BEGIN OF and END OF.
  • LOB handle structures can also be derived in the ABAP Dictionary. A function is provided for this purpose when database tables or views that contain LOBs are displayed.
  • If dbtab does not contain any LOBs that match the column specifications, no LOB handle components are created and the statement creates a normal work area.
  • If dbtab is enhanced later by LOBs which match the column specifications ALL [OTHER] ..., then LOB handle components are also created for these.


Example

Refer to Deriving LOB handle structures.

Continue

TYPES - lob_handle_type

TYPES - lob_handle_columns

Deriving LOB Handle Structures