Creates a storage map for a relation.  A storage map associates a
 relation with a particular storage area or areas.  The DEFINE STORAGE
 MAP statement allows you to specify:

  o  Which storage areas the records in a relation will be stored in
  o  Whether an index will be used to choose a target location for
     storing the record
  o  Whether data compression will be enabled when the records are
     stored


 Example:

    RDO>   DEFINE STORAGE MAP JOBS_MAP FOR JOBS
    cont>    STORE WITHIN JOBS
    cont>  END JOBS_MAP STORAGE MAP.

Additional information available:

FormatExamples

 DEFINE STORAGE MAP ───────────> map-name ──────────────┐
 ┌────────────────────────<─────────────────────────────┘
 └──────┬─────────────────────>───────────┬────────────────────┐
        └─> 
D
E
S
C
R
I
P
T
I
O
N typebox (I)typebox (S) typebox (/)typebox (*)  text  */ ──┘                    │
 ┌─────────────────────────────────────────────────────────────┘
 └───> 
F
O
R  ────────────> relation-map-clause ────────────────────┐
  ┌───────────────────────────────<───────────────────────────────┘
  └──────────> 
E
N
D ─────┬───────────────┬─────> typebox (S)typebox (T)typebox (O)typebox (R)typebox (A)typebox (G)typebox (E) typebox (M)typebox (A)typebox (P) ───────> .
                        └─> map-name ───┘

Additional information available:

map-nametextrelation-map-clause

 Specifies the name for the storage map being defined.

 A text string that adds a comment to the storage map definition.

 relation-map-clause =

 ───────>  relation-name ──────> typebox (R)typebox (E)typebox (L)typebox (A)typebox (T)typebox (I)typebox (O)typebox (N) ──────────>───────────┐
     ┌─────────────────────────────<────────────────────────────┘
     │
     └──┬──┬─> store-clause ─────────────────────────┬──────┬──>
        │  ├─> 
P
L
A
C
E
M
E
N
T 
V
I
A 
I
N
D
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X ───> index-name ──┤      │
        │  └────┬──> 
D
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S
A
B
L
E ──┬─> 
C
O
M
P
R
E
S
S
I
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N ──────┘      │
        │       └──> 
E
N
A
B
L
E ───┘                            │
        │                                                   │
        └──────────────────────────<────────────────────────┘

Additional information available:

PLACEMENT_VIA_INDEX

relation-namestore-clauseCOMPRESSION clause

 Specifies the relation to which the storage map will apply.  The
 relation must already be defined and cannot have a storage map
 associated with it.

 store-clause =

 STORE ─┬──> 
W
I
T
H
I
N ─┬──> storage-area-name ────┬─────>──────────┬──>
 ┌──────┘            └───────  typebox (;) <──────────────┘                │
 │                                                               │
 └─────> 
U
S
I
N
G ───┬────> field-name ───┬── 
W
I
T
H
I
N ────>──────┐   │
                  └────────── , ───────┘                     │   │
 ┌───────────────────────────────<───────────────────────────┘   │
 └─┬─>storage-area-name ──>
W
I
T
H 
L
I
M
I
T typebox (O)F─┬> literal ─┬─ typebox (;) ──┬─┐  │
   │                                     └──── , <───┘      │ │  │
   └──────────────────────────<─────────────────────────────┘ │  │
 ┌────────────────────────────<───────────────────────────────┘  │
 │                                                               │
 └────────────────────> storage-area-name ─────────>─────────────┘

Additional information available:

WITH_LIMIT_OF

field-namestorage-area-name

 The names of the fields whose values will be used as limits for
 partitioning the relation across multiple storage areas.

 The name of the storage area you want records stored in.  You must
 define this storage area with the DEFINE DATABASE statement before
 you refer to it in the store clause.

 The WITH LIMIT OF clause specifies the maximum value the key defined
 in the USING clause can have when it is initially stored in the
 specified storage area.

 The number of literals specified must match the number of fields
 specified in the USING clause.

 If you change the limits for a storage area, records that were
 already stored in the area are not moved according to the new limit
 clause.  However, new records will be stored according to the new
 limits that you specify.

 Indicates that Rdb/VMS should attempt to store a record in a way that
 optimizes access to that record via the indicated path.  Rdb/VMS
 chooses a target page for any record being stored by rules that take
 into account the type of index defined (sorted or hashed), the type
 of storage areas involved (uniform or mixed) and how indexes and
 relations are assigned to each other.

 Specifies whether data compression will be enabled or disabled when
 the records are stored.  ENABLE COMPRESSION is the default.

 Example 1

 The following statement defines a storage map for the employees
 relation in MF_PERSONNEL.

 DEFINE STORAGE MAP EMPLOYEES_MAP
    DESCRIPTION IS /* EMPLOYEES partitioned by EMPLOYEE_ID */
    FOR EMPLOYEES RELATION
  STORE USING EMPLOYEE_ID
   WITHIN
    EMPIDS_LOW WITH LIMIT OF "00200";
    EMPIDS_MID WITH LIMIT OF "00400";
    EMPIDS_OVER
 END EMPLOYEES_MAP STORAGE MAP.

 Example 2

 The following example shows how to define a storage map that stores
 all records from a relation in the named storage area:


 RDO>  DEFINE STORAGE MAP SALARY_HISTORY_MAP
 cont>  DESCRIPTION IS /* Map for salary history records */
 cont>  FOR SALARY_HISTORY RELATION
 cont>   STORE WITHIN SALARY_HISTORY
 cont> END SALARY_HISTORY_MAP STORAGE MAP.

 This statement stores all the records from the SALARY_HISTORY
 relation into the storage area, SALARY_HISTORY.  SALARY_HISTORY is
 the name of a storage area that was created with the DEFINE DATABASE
 statement.

 Example 3

 The following example uses the PLACEMENT VIA clause to store records
 in a storage area according to a hashed index:


 RDO>   DEFINE STORAGE MAP DEPARTMENTS_MAP
 cont>    FOR DEPARTMENTS RELATION
 cont>    STORE WITHIN DEPARTMENTS
 cont>    PLACEMENT VIA INDEX DEPARTMENTS_INDEX
 cont>  END DEPARTMENTS_MAP STORAGE MAP.