XML to DDL

Question

HI
I'm using DBMS_METADATA.GET_SXML to retreive the dll in xml. Its in XML becuase I need a way to process each table's column, constraints etc, inidividually and xml nodes helps do this. Once processed the node(s) need to be transformed back into ddl format. Tthere can be many variations with regards to the data content witin the nodes e.g. in the xml below "COUNTRY_ID" has a CONSTRAINT NOT NULL and "COUNTRY_NAME" with no CONSTRAINTS?, this indicates xslt has to be aware of these factors. Perhaps someone has a more efficient approach, any suggestions and tips will be helpful. Thanks
<TABLE xmlns="http://xmlns.oracle.com/ku" version="1.0">
<SCHEMA>HR</SCHEMA>
<NAME>COUNTRIES</NAME>
<RELATIONAL_TABLE>
<COL_LIST>
<COL_LIST_ITEM>
<NAME>COUNTRY_ID</NAME>
<DATATYPE>CHAR</DATATYPE>
<LENGTH>2</LENGTH>
<NOT_NULL>
<NAME>COUNTRY_ID_NN</NAME>
</NOT_NULL>
</COL_LIST_ITEM>
          <COL_LIST_ITEM>
<NAME>COUNTRY_NAME</NAME>
<DATATYPE>VARCHAR2</DATATYPE>
<LENGTH>40</LENGTH>
</COL_LIST_ITEM>
<PRIMARY_KEY_CONSTRAINT_LIST>
<PRIMARY_KEY_CONSTRAINT_LIST_ITEM>
<NAME>COUNTRY_C_ID_PK</NAME>
<COL_LIST>
<COL_LIST_ITEM>
<NAME>COUNTRY_ID</NAME>
</COL_LIST_ITEM>
</COL_LIST>
</PRIMARY_KEY_CONSTRAINT_LIST_ITEM>
</PRIMARY_KEY_CONSTRAINT_LIST>
<FOREIGN_KEY_CONSTRAINT_LIST>
<FOREIGN_KEY_CONSTRAINT_LIST_ITEM>
<NAME>COUNTR_REG_FK</NAME>
<COL_LIST>
<COL_LIST_ITEM>
<NAME>REGION_ID</NAME>
</COL_LIST_ITEM>
</COL_LIST>
<REFERENCES>
<SCHEMA>HR</SCHEMA>
<NAME>REGIONS</NAME>
<COL_LIST>
<COL_LIST_ITEM>
<NAME>REGION_ID</NAME>
</COL_LIST_ITEM>
</COL_LIST>
</REFERENCES>
</FOREIGN_KEY_CONSTRAINT_LIST_ITEM>
</FOREIGN_KEY_CONSTRAINT_LIST>

Answer 1

Hi,
Not sure what you're asking.
Do you want to convert back the XML to DDL once you've made your changes?
If so, the Metadata APIs already provide such functionality, provided the structure is still valid of course.
For example :
SQL> DECLARE
  2    -- handles
  3    h            number;
  4    th           number;
  5
  6    source_doc   XMLType := XMLType(dbms_metadata.get_sxml('TABLE', 'COUNTRIES', 'HR'));
  7    target_doc   XMLType;
  8
  9    ddl          clob;
10
11  BEGIN
12
13   -- this increases the length of VARCHAR2 columns by 10 :
14   select xmlquery(
15   'declare default element namespace "http://xmlns.oracle.com/ku"; (: :)
16    copy $d := /TABLE
17    modify (
18      for $i in $d/RELATIONAL_TABLE/COL_LIST/COL_LIST_ITEM
19      where $i/DATATYPE = "VARCHAR2"
20      return replace value of node $i/LENGTH with xs:integer($i/LENGTH)+10
21    )
22    return $d'
23    passing source_doc
24    returning content
25    )
26    into target_doc
27    from dual;
28
29    h := dbms_metadata.openw('TABLE');
30    th := dbms_metadata.add_transform(h, 'SXMLDDL');
31
32    dbms_lob.createtemporary(ddl, false);
33    dbms_metadata.convert(h, target_doc, ddl);
34    dbms_metadata.close(h);
35
36    dbms_output.put_line(ddl);
37    dbms_lob.freetemporary(ddl);
38
39  END;
40  /
CREATE TABLE "HR"."COUNTRIES"
   (    "COUNTRY_ID" CHAR(2) CONSTRAINT "COUNTRY_ID_NN" NOT NULL ENABLE,
        "COUNTRY_NAME" VARCHAR2(50),
        "REGION_ID" NUMBER,
        CONSTRAINT "COUNTRY_C_ID_PK" PRIMARY KEY
("COUNTRY_ID") ENABLE,
        CONSTRAINT "COUNTR_REG_FK" FOREIGN KEY ("REGION_ID")
         REFERENCES "HR"."REGIONS" ("REGION_ID") ENABLE
   ) ORGANIZATION INDEX NOCOMPRESS PCTFREE 10 INITRANS 2 NOLOGGING
STORAGE( INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
  TABLESPACE
"EXAMPLE"
  PCTTHRESHOLD 50
Procédure PL/SQL terminée avec succès.