How to create a LIST partitioned table in PostgreSQL

Create the table:

CREATE TABLE DOCUMENTS(
  DOC_ID                      INTEGER  NOT NULL,
  LEGAL_ENTITY                INTEGER       NULL,
  CREATED_DT                  DATE      NOT NULL,
  REGION                      VARCHAR(30)   NULL,
  DOCUMENTTYPE                VARCHAR(100)  NULL,
  DOCUMENTNAME                VARCHAR(1000) NULL
)
PARTITION BY LIST (DOCUMENTTYPE);

Create a couple of partitions, including a default partition:

CREATE TABLE P_SUBPOENAS PARTITION OF  DOCUMENTS FOR VALUES IN  ('SUBPOENA');
CREATE TABLE P_AFFIDAVITS PARTITION OF DOCUMENTS FOR VALUES IN  ('AFFIDAVIT');
CREATE TABLE P_MEMORANDOMS PARTITION OF DOCUMENTS FOR VALUES IN ('MEMORANDOM');
CREATE TABLE P_DEFAULT PARTITION OF DOCUMENTS DEFAULT;

To add a primary key to a partitioned table, read this post

If your LIST-partitioned table would benefit from sub-partitioning, read this post