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ABENABAP_MANAGED_DB_OBJECTS_NSQL - ABAP MANAGED DB OBJECTS NSQL

ABENABAP_MANAGED_DB_OBJECTS_NSQL - ABAP MANAGED DB OBJECTS NSQL

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Native SQL Access to ABAP-Managed Database Objects

There are two types of Native SQL access to ABAP-managed database objects.

Access Using ABAP-Managed Native SQL

ABAP-managed Native SQL is Native SQL that can be used by ABAP programs to access the database through the Native SQL interface in AS ABAP. It includes the following:

The Native SQL interface passes vendor-specific SQL statements to the database system without making any modifications. Alongside this, SAP-specific Native SQL is available, which is processed in platform-dependent parts of the interface (Client Libraries).

Native SQL can be used to access ABAP-managed database objects as follows:

  • Reads and writes on the following ABAP-managed database objects using database-specific SQL:

  • SQL views of CDS views defined in ABAP CDS.

  • Calls of the following ABAP-managed database procedures or database functions:

The most important features of Native SQL are as follows:

  • Native SQL is platform-dependent.
  • Data types defined in the ABAP Dictionary and their possible enhancements are not currently known in Native SQL.
  • Native SQL does not respect the order of fields defined in the ABAP Dictionary, which can differ from the order in the database.

  • The platform-dependent parts (Client Libraries) of the Native SQL interface support mappings between ABAP types and appropriate database types for bound parameters in ADBC and host variables after EXEC SQL. If types are not appropriate, on the other hand, platform-dependent conversions are made, which can easily produce unexpected results and errors.

  • Any null values passed to ABAP data objects using the Native SQL interface are transformed to their type-dependent initial values. In the case of writes, null values cannot be prevented.

  • When procedures are called, Native SQL provides the following special methods alongside the platform-dependent SQL statements:

  • When AMDP procedures and AMDP functions are called, it cannot be guaranteed that the database objects exist or that their content is up-to-date. This is only the case in calls from ABAP and when accessing objects using . Before an object is accessed using Native SQL, methods of the documented class CL_AMDP_RUNTIME_SERVICES can be used to create the database objects. This applies both to direct calls and indirect cases, such as when SQL views of CDS views are accessed in whose DDL source code CDS table functions are used as a data source.
  • Native SQL does not support the following ABAP Dictionary and ABAP CDS functions:
  • Native SQL does not support implicit client handling. The client ID must always be specified explicitly. To do this, a parameter must be bound in ADBC or a host variable must be used after EXEC SQL. The ABAP-specific session variables CLIENT and CDS_CLIENT can be accessed on the SAP HANA database. It should be noted here that, when using Native SQL, the value of the session variable CDS_CLIENT cannot be set to a different value using ABAP methods.

  • Native SQL accesses the database objects of CDS entities directly and ignores any other properties of CDS entities:
  • When the CDS-managed DDIC view of a CDS view is accessed, the database-specific instance created of this view must be known. This applies in particular to CDS views with input parameters.

  • When an instance of a CDS table function is accessed, its AMDP table function must be called.

  • It must be ensured that all session variables used in a CDS view entity or have the correct value. This applies in particular to the session variable client, to which the HANA session variable CDS_CLIENT is assigned and not CLIENT.

  • The ABAP-managed database objects accessed in Native SQL are not recorded in a where-used list. Where-used lists can only be created indirectly, by declaring suitable parameters and host variables in references to the dictionary types of the database objects. Another option is a full text search in the ABAP source code in AS ABAP.
  • DDL statements are allowed in Native SQL.
  • When ADBC is used, Native SQL is either fully dynamic or, if EXEC SQL is used, fully static.

Access Using Non-ABAP-Managed Native SQL

Non-ABAP-managed Native SQL consists of SQL statements that are passed to the database using interfaces other than the Native SQL interface of AS ABAP or that are executed in the database without being checked in AS ABAP. Examples are database objects in the SAP HANA database created by SAP Web IDE for SAP HANA that access ABAP-managed database objects, views that access database tables in ABAP Dictionary, or database procedures that call AMDP procedures or functions.

In general, the same applies to access using non-ABAP-managed Native SQL as to accessing ABAP-managed Native SQL. There are, however, the following additional restrictions:

  • The implementation and function of a database object managed by ABAP can depend on ABAP-specific context information that is provided only in cases where the database is a standard AS ABAP database and addressed using its database interface. More specifically, the content of the ABAP-specific session variables in the SAP HANA database can be set correctly only when an object is accessed from ABAP. On other database platforms, in fact, only CDS session variables are set when CDS entities are accessed using .
  • Only in cases where access is made from AS ABAP can it be guaranteed that an ABAP-managed database object actually exists and its content is up-to-date. The time when the instance is created or updated is not fixed and the existence or consistency of the instance is not guaranteed for access from outside AS ABAP. This applies in particular to AMDP procedures and AMDP functions whose existence and consistency is only guaranteed by the AMDP framework of AS ABAP.
  • A where-used list for ABAP-managed database objects cannot be found using non-ABAP-managed Native SQL.

Note

A dependency rule defined for a database table is also respected by non-ABAP-managed Native SQL, since this rule is evaluated by the optimizer of the SAP HANA database.






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