Is this trying to create a PK index twice?

Question

When Application Express writes out a .sql file, it has the following:
CREATE TABLE "HTMLBITMAPS"
(     "BMNAME" CHAR(32) NOT NULL ENABLE,
     "BMDATA" BLOB NOT NULL ENABLE,
     "BMFORMAT" NUMBER(3,0) NOT NULL ENABLE,
     "REPORTID" NUMBER(38,0) NOT NULL ENABLE,
     CONSTRAINT "PK_HTMLBITMAPS" PRIMARY KEY ("BMNAME") ENABLE
CREATE UNIQUE INDEX "PK_HTMLBITMAPS" ON "HTMLBITMAPS" ("BMNAME")
But when I then run the script the create unique ... is an error as an index with that name already exists. Does the constraint... in the table declaration already create the index and this additional command is an error in the .sql Application Express generates?
thanks - dave

Answer 1

Does the constraint... in the table declaration already create the index Yes, it does.
http://download-uk.oracle.com/docs/cd/B10501_01/server.920/a96524/c22integ.htm#11102
Oracle enforces primary key constraints using indexes, and composite primary key constraints are limited to 32 columns, which is the same limitation imposed on composite indexes. The name of the index is the same as the name of the constraint. Also, you can specify the storage options for the index by including the ENABLE clause in the CREATE TABLE or ALTER TABLE statement used to create the constraint. If a usable index exists when a primary key constraint is created, then the primary key constraint uses that index rather than implicitly creating a new one.
http://download-uk.oracle.com/docs/cd/B10501_01/server.920/a96540/statements_73a.htm#2062567
If you enable a unique or primary key constraint, and if no index exists on the key, Oracle creates a unique index. This index is dropped if the constraint is subsequently disabled, and Oracle rebuilds the index every time the constraint is enabled.
To avoid rebuilding the index and eliminate redundant indexes, create new primary key and unique constraints initially disabled. Then create (or use existing) nonunique indexes to enforce the constraint. Oracle does not drop a nonunique index when the constraint is disabled, so subsequent ENABLE operations are facilitated.
It could look like:
SQL> CREATE TABLE "HTMLBITMAPS"
  2  ( "BMNAME" CHAR(32) NOT NULL ENABLE,
  3  "BMDATA" BLOB NOT NULL ENABLE,
  4  "BMFORMAT" NUMBER(3,0) NOT NULL ENABLE,
  5  "REPORTID" NUMBER(38,0) NOT NULL ENABLE,
  6  CONSTRAINT "PK_HTMLBITMAPS" PRIMARY KEY ("BMNAME") DISABLE
  7  )
  8  /
Table created.
SQL> CREATE INDEX "PK_HTMLBITMAPS" ON "HTMLBITMAPS" ("BMNAME")
  2  /
Index created.
SQL> ALTER TABLE "HTMLBITMAPS" ENABLE PRIMARY KEY
  2  /
Table altered.Rgds.