what is the interface between the abap dictionary and the underlying database management system
The interface between the ABAP Dictionary and the underlying Database Management System (DBMS) is established through the Open SQL interface. Open SQL is a subset of the Structured Query Language (SQL) that allows ABAP programs to interact with the database.
The ABAP Dictionary provides a central repository for defining and managing database objects, such as tables, views, indexes, and data types. These definitions are stored in the ABAP Dictionary and are used to generate the corresponding database-specific structures and statements.
When an ABAP program needs to access data from the database, it can use Open SQL statements to retrieve, insert, update, or delete records. These Open SQL statements are written in ABAP and are translated into the appropriate database-specific SQL statements at runtime.
The ABAP runtime environment, also known as the Database Interface (DBI), is responsible for translating the Open SQL statements into the corresponding DBMS-specific SQL statements. The DBI communicates with the underlying DBMS using database-specific communication protocols, such as ODBC or JDBC.
The DBI handles tasks such as connecting to the database, executing the SQL statements, and retrieving the results. It also provides error handling and transaction management capabilities.
In summary, the interface between the ABAP Dictionary and the underlying DBMS is established through the Open SQL interface. This interface allows ABAP programs to interact with the database by using ABAP-based Open SQL statements, which are translated into DBMS-specific SQL statements at runtime by the ABAP runtime environment or Database Interface.