title: postgreSQL uuid generation
body: <pre><code>select uuid_generate_v4() as one, uuid_generate_v4() as two;
  </code></pre>
  
  <p>"one" uuid and "two" uuid are equal!</p>
  
  <pre><code>CREATE TABLE "TB"
  (
    "Id" uuid NOT NULL DEFAULT uuid_generate_v4(),
    "Title" character varying NOT NULL,
     CONSTRAINT "TB_Class_ID" PRIMARY KEY ("Id")
  );
  </code></pre>
  
  <p>postgresql 9.0 pgAdmin 1.12.3</p>
  
  <pre><code>insert into "TB" ("Id", "Title") values (uuid_generate_v4(), '111');
  insert into "TB" ("Id", "Title") values (uuid_generate_v4(), '111');
  insert into "TB" ("Id", "Title") values (uuid_generate_v4(), '111');
  </code></pre>
  
  <p>or</p>
  
  <pre><code>insert into "TB" ("Title") values ('111');
  insert into "TB" ("Title") values ('111');
  insert into "TB" ("Title") values ('111');
  </code></pre>
  
  <p>result:</p>
  
  <pre><code>ERROR:  duplicate key value violates unique constraint "TB_Class_ID"
  DETAIL:  Key ("Id")=(12ab6634-995a-4688-9a9a-ee8c3fe24395) already exists.
  </code></pre>
  
  <p>whereas</p>
  
  <p>postgreSQL maestro 9.2.0.4</p>
  
  <pre><code>insert into "TB" ("Id", "Title") values (uuid_generate_v4(), '111');
  insert into "TB" ("Id", "Title") values (uuid_generate_v4(), '111');
  insert into "TB" ("Id", "Title") values (uuid_generate_v4(), '111');
  </code></pre>
  
  <p>result: 1 rows affected;</p>
  
  <p>I understand that maestro added records one by one, but why uuid_generate_v4() returns the same value after two calls? (In pgAdmin case).</p>
  
  <p>And how can I add several rows by one request?</p>