The ultimate flexible database schema

gistfile1.sql

CREATE TABLE "database"
(
  id serial NOT NULL,
  name text,
  CONSTRAINT database_pkey PRIMARY KEY (id)
)

CREATE TABLE "table"
(
  id serial NOT NULL,
  database_id integer,
  name text,
  CONSTRAINT table_pkey PRIMARY KEY (id),
  CONSTRAINT table_database_id_fkey FOREIGN KEY (database_id)
      REFERENCES "database" (id)
)

CREATE TABLE "column"
(
  id serial NOT NULL,
  table_id integer,
  name text,
  CONSTRAINT column_pkey PRIMARY KEY (id),
  CONSTRAINT column_table_id_fkey FOREIGN KEY (table_id)
      REFERENCES "table" (id)
)

CREATE TABLE "row"
(
  id serial NOT NULL,
  table_id integer,
  CONSTRAINT row_pkey PRIMARY KEY (id),
  CONSTRAINT row_table_id_fkey FOREIGN KEY (table_id)
      REFERENCES "table" (id)
)

CREATE TABLE "value"
(
  id serial NOT NULL,
  column_id integer,
  row_id integer,
  value text,
  CONSTRAINT value_pkey PRIMARY KEY (id),
  CONSTRAINT value_column_id_fkey FOREIGN KEY (column_id)
      REFERENCES "column" (id)
  CONSTRAINT value_row_id_fkey FOREIGN KEY (row_id)
      REFERENCES "row" (id)
)