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Horst Keller has already introduced ADBC in his blog ABAP Geek 15 – ADBC long times ago. And recently during my self study on PostgreSQL I made some practice to connect PostgreSQL in Java programming using Java Database Connectivity – JDBC. In fact I found out that there are lots of commonality between these two technologies. There is a demo program demo_adbc_query mentioned in SAP help to demonstrate the use of ADBC. I make some changes on it in order to perform a line-by-line comparison with JDBC. The source code of adapted program: REPORT zjerry_adbc.CLASS demo DEFINITION. PUBLIC SECTION. CLASS-METHODS main. PRIVATE SECTION. CLASS-DATA: BEGIN OF result_line, carrid TYPE sflight-carrid, connid TYPE sflight-connid, fldate TYPE sflight-fldate, END OF result_line, result_tab LIKE TABLE OF result_line.ENDCLASS.CLASS demo IMPLEMENTATION. METHOD main. DATA: carrid TYPE sflight-carrid VALUE 'AA', cols TYPE adbc_column_tab, lv_carrid TYPE string, con_ref TYPE REF TO cl_sql_connection, con_name TYPE dbcon-con_name VALUE 'DEFAULT'. cols = VALUE #( ( CONV adbc_name( 'CARRID' ) ) ( CONV adbc_name( 'CONNID' ) ) ( CONV adbc_name( 'FLDATE' ) ) ). lv_carrid = cl_abap_dyn_prg=>quote( to_upper( carrid ) ). TRY. con_ref = cl_sql_connection=>get_connection( con_name ). DATA(statement) = con_ref->create_statement( ). DATA(lv_query) = `SELECT carrid, connid, fldate ` && `FROM sflight ` && `WHERE mandt = ` && `'` && sy-mandt && `' AND` && ` carrid = ` && lv_carrid. DATA(result) = statement->execute_query( lv_query ). result->set_param_table( itab_ref = REF #( result_tab ) corresponding_fields = cols ). IF result->next_package( ) > 0. SORT result_tab BY carrid connid fldate. WRITE:/ 'Number of lines found: ', lines( result_tab ). ENDIF. con_ref->close( ). CATCH cx_sql_exception INTO DATA(err). ENDTRY. ENDMETHOD.ENDCLASS.START-OF-SELECTION. demo=>main( ). And now have a look at how JDBC can achieve the same. I have replicated an ABAP table COMM_PRODUCT to my local PostgreSQL server:
And I manually inserted two test records into it:
Both is the source code implemented in Java to perform a query against this table and display result： import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import java.sql.Timestamp;public class PostgreSQLJDBC { private Connection connection = null; private void select() { try { int index = 0; Class.forName("org.postgresql.Driver"); connection = DriverManager.getConnection( "jdbc:postgresql://localhost:9812/zproduct", "postgres", "XXXXXX"); Statement stmt = connection.createStatement(); String query = "SELECT * FROM public.comm_product;"; ResultSet rs = stmt.executeQuery(query); while ( rs.next() ) { System.out.println("Row index: " + index++); String client = rs.getString("client"); System.out.println("Client: " + client); String guid = rs.getString("product_guid"); System.out.println("Product guid: " + guid); Timestamp validFrom = rs.getTimestamp("valid_from"); System.out.println("Valid from: " + validFrom); } rs.close(); stmt.close(); connection.close(); } catch (Exception e) { e.printStackTrace(); } } public static void main(String args[]) { PostgreSQLJDBC jdbcTest = new PostgreSQLJDBC(); jdbcTest.select(); }}Output in console:
And I mark the corresponding part in both language which has the same semantic meaning with same color ( although grammar is different ). Through this comparison we can know that both connectivity technology follow the same idea.
Further readingI have written a series of blogs which compare the language feature among ABAP, JavaScript and Java. You can find a list of them below:
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