Fix support for newid() from MS SQL.

Several places in the code are involved to deal with the default values from
MS SQL. The catalog query is dealing with strange quoting rules on the
source side and used to fill in directly the PostgreSQL expected value. But
then the quoting of a function call wasn't properly handled.

Rather than coping with the quoting rules here, have the catalog query
return a pgloader specific placeholder "GENERATE_UUID". Then the MS SQL
specific code can normalize that to the symbol :generate_uuid. Then the
generic PostgreSQL DDL code can implement the proper replacement for that
symbol, not having to know where it comes from.

Fix #742.

src/pgsql/pgsql-ddl.lisp

@@ -122,7 +122,7 @@
   '((:null              . "NULL")
     (:current-date      . "CURRENT_DATE")
     (:current-timestamp . "CURRENT_TIMESTAMP")
-    (:generate-uuid     . "uuid_generate_v1()"))
+    (:generate-uuid     . "uuid_generate_v4()"))
   "Common normalized default values and their PostgreSQL spelling.")
 
 (defmethod format-default-value ((column column) &key (stream nil))

src/sources/mssql/mssql-cast-rules.lisp

@@ -159,7 +159,8 @@
 
                 ((and (stringp default)
                       (or (string= "newid()" default)
-                          (string= "newsequentialid()" default)))
+                          (string= "newsequentialid()" default)
+                          (string= "GENERATE_UUID" default)))
                  :generate-uuid)
 
                 (t (column-default pgcol)))))

src/sources/mssql/sql/list-all-columns.sql

@@ -11,15 +11,15 @@
          CASE
          WHEN c.COLUMN_DEFAULT LIKE '((%' AND c.COLUMN_DEFAULT LIKE '%))' THEN
              CASE
-                 WHEN SUBSTRING(c.COLUMN_DEFAULT,3,len(c.COLUMN_DEFAULT)-4) = 'newid()' THEN 'generate_uuid_v4()'
+                 WHEN SUBSTRING(c.COLUMN_DEFAULT,3,len(c.COLUMN_DEFAULT)-4) = 'newid()' THEN 'GENERATE_UUID'
                  WHEN SUBSTRING(c.COLUMN_DEFAULT,3,len(c.COLUMN_DEFAULT)-4) LIKE 'convert(%varchar%,getdate(),%)' THEN 'today'
                  WHEN SUBSTRING(c.COLUMN_DEFAULT,3,len(c.COLUMN_DEFAULT)-4) = 'getdate()' THEN 'CURRENT_TIMESTAMP'
                  WHEN SUBSTRING(c.COLUMN_DEFAULT,3,len(c.COLUMN_DEFAULT)-4) LIKE '''%''' THEN SUBSTRING(c.COLUMN_DEFAULT,4,len(c.COLUMN_DEFAULT)-6)
                  ELSE SUBSTRING(c.COLUMN_DEFAULT,3,len(c.COLUMN_DEFAULT)-4)
              END
          WHEN c.COLUMN_DEFAULT LIKE '(%' AND c.COLUMN_DEFAULT LIKE '%)' THEN
              CASE
-                 WHEN SUBSTRING(c.COLUMN_DEFAULT,2,len(c.COLUMN_DEFAULT)-2) = 'newid()' THEN 'generate_uuid_v4()'
+                 WHEN SUBSTRING(c.COLUMN_DEFAULT,2,len(c.COLUMN_DEFAULT)-2) = 'newid()' THEN 'GENERATE_UUID'
                  WHEN SUBSTRING(c.COLUMN_DEFAULT,2,len(c.COLUMN_DEFAULT)-2) LIKE 'convert(%varchar%,getdate(),%)' THEN 'today'
                  WHEN SUBSTRING(c.COLUMN_DEFAULT,2,len(c.COLUMN_DEFAULT)-2) = 'getdate()' THEN 'CURRENT_TIMESTAMP'
                  WHEN SUBSTRING(c.COLUMN_DEFAULT,2,len(c.COLUMN_DEFAULT)-2) LIKE '''%''' THEN SUBSTRING(c.COLUMN_DEFAULT,3,len(c.COLUMN_DEFAULT)-4)