2532300 - Error "DDL Source" "BSAD_DDL" could not be activated in ACT_UPG phase.

In ACT_UPG phase, the following error can be found:

  ==

  1EEDO519X"DDL Source" "BSAD_DDL" could not be activated
  1EEDO519 "DDL Source" "BSAK_DDL" could not be activated
  1EEDO519 "DDL Source" "BSAS_DDL" could not be activated
  1EEDO519 "DDL Source" "BSIS_DDL" could not be activated
  1EEDO519 "DDL Source" "FAGLBSAS_DDL" could not be activated
  1EEDO519 "DDL Source" "FAGLBSIS_DDL" could not be activated

  ==

  Or Error:

  ==

  1EEMC705 Key fields are not together at the beginning of the view

   ===

SAP Basis 750 up to patch level 09

SAP Basis 751 up to patch level 04

BSAD_DDL,BSAK_DDL,BSAS_DDL,BSIS_DDL,ACT_UPG,SUM,Upgrade, 1EEMC705, Key fields are not together at the beginning of the view, CDS View. , KBA , BC-DWB-DIC-AC , ABAP Dictionary Activation and Conversion , BC-UPG-TLS-TLA , Upgrade tools for ABAP , Problem