CREATE DSMODEL

The CREATE DSMODEL utility defines a temporary model of data set attributes to use for dynamic file allocation in conjunction with the REORG utility.
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The CREATE DSMODEL utility defines a temporary model of data set attributes to use for dynamic file allocation in conjunction with the REORG utility.
This article describes the following information:
 
 
2
 
2
 
 
Authorization
None.
Syntax
►►─CREATE DSMODEL ─ model-name┬────────────────────────┬dataset-attribute-spec─►◄ └FROM existing-model-name┘
Expansion of
 
dataset-attribute-spec
 
┌────────────────────────────────────────────────────────────┐ ►►──▼──┬─ DSN ─ dsn-expression ────────────────────────────────┬─┴─────────────►◄ ├─ UNIT ─ unit-name ────────────────────────────────────┤ ├─ VOLSER ─┬ volser ──────────┬─────────────────────────┤ │ │ ┌───, ─────┐ │ │ │ └ (─▼─ volser ─┴─) ┘ │ ├─ VOLCNT ─ volume-count ───────────────────────────────┤ ├─ SPACE ┬ CYL ◄────┬───( primary ┬──────────────┬)─────┤ │ ├ TRK ─────┤ └ ,secondary───┘──────│ │ └ blksize ─┘ │ ├─ BLKSIZE ─ block-size ────────────────────────────────┤ ├─ BUFNO ─ number-of-buffers ───────────────────────────┤ ├─ DATACLAS ─ data-class ───────────────────────────────┤ ├─ MGMTCLAS ─ management-class ─────────────────────────┤ ├─ STORCLAS ─ storage-class ────────────────────────────┤ └─ DSNTYPE ┬ EXTREQ ───┬────────────────────────────────┘ ├ EXTPREF ──┤ ├ LARGE ────┤ └ BASIC ────┘
Expansion of
 
dsn-expression
 
►►── ' ┬────────────────┬─┬─ character-string ─┬─ ' ───────────────────────────►◄ │ ┌─────. ─────┐ │ └─ dsn-variable ─────┘ └─▼─ dsn-term ─┴─┘
Expansion of
 
dsn-term
 
►►──┬─ character-string ─┬────────────────────┬────────────────────────────────►◄ │ └─ dsn-variable ─────┤ └─ dsn-variable ──────────────────────────┘
Expansion of
 
dsn-variable
 
►►── dsn-variable-name ─┬────────────────────────────┬─────────────────────────►◄ └─ ( start ┬────────────┬ ) ─┘ └─ , length ─┘
Expansion of
 
dsn-variable-name
 
►►── &DD. ─────────────────────────────────────────────────────────────────────►◄
Parameters
  • model-name
     
    Specifies the name of the data set model being created. 
    Model-name
     must be 1 to 18 characters. If the last non-blank character of 
    model-name
     is an asterisk (*), it matches any search string whose value begins with the character string to the left of the asterisk in the model name. A model name consisting of a single asterisk matches all search keys.
  • existing-model-name
     
    Specifies the name of an existing data set model whose attributes are to be copied to the model being created.
  • dataset-attribute-spec
     
    Specifies attributes of the data set model.
  • dsn-expression
     
    Specifies an expression used to construct data set names.
  • unit-name
     
    Specifies the unit type on which the file resides or will reside.
  • volser
     
    Specifies the name of a volume on which the file resides or will reside.
  • volume-count
     
    Specifies the maximum number of volumes on which the file can reside. The default is the operating system default.
  • CYL/TRK/
    blksize
     
    Specifies the allocation unit for a disk data set. CYL allocates the file in units of cylinders. TRK allocates the file in units of tracks. 
    Blksize
     allocates the file in units whose size is 
    blksize
    .
  • primary
     
    Specifies the number of units in the primary allocation for a disk file.
  • secondary
     
    Specifies the number of units in the secondary allocation for a disk file.
  • block-size
     
    Specifies the blocksize to be used in creating (and accessing) a new file.
  • number-of-buffers
     
    Specifies the number of buffers to be used in accessing a file.
  • data-class, management-class, storage-class, dataset-type
     
    Specifies a data set's SMS data class, management class, storage class, and dataset type respectively
  • DSNTYPE
     
    Specifies the type attribute for new SMS-managed data sets. DSNTYPE overrides the DSNTYPE defined in the data class of a new data set. If SMS is not active, DSNTYPE is ignored.
    • EXTREQ
       
      Specifies extended format. This option is valid for VSAM and sequential data sets only.
    • EXTPREF
       
      Specifies extended as the preferred format. The data set is allocated as extended if it is either VSAM or sequential; otherwise, it will be allocated as a basic format data set.
    • L
      ARGE
       
      Specifies large format. This option is valid for sequential non-VSAM data sets only.
    • BASIC
       
      Specifies basic format. This option is valid for sequential non-VSAM data sets only.
  • dsn-variable-name
     
    Specifies the name of a symbolic variable whose value can be used in whole or in part as a substitution parameter in the construction of a data set name.
    • &DD.
      Specifies the DDNAME (linkname) through which the data set is referenced.
  • start
     
    Specifies the position of the first character in the value of the symbolic variable that is to be used in the construction of the data set name. Start must not identify a position beyond the last non-blank character in the value.
  • length
     
    Specifies the number of characters in the value of the symbolic variable that are to be used in the construction of the data set name. If not specified, 
    length
     defaults to the number of non-blank characters from the start character to the end of the value. Trailing blank characters are truncated.
Usage
Using data set models
Data set models are currently used only to specify attributes of the work files used by the REORG utility. For more information about how it uses data set models, see REORG.
 
Data set model duration
Data set models are transient entities that, once created, exist in memory for the life of the database session in which they are created. They are not stored in a dictionary.
Defining dummy files
You can define attributes for a dummy file by creating a data set model whose 
dsn-expression
 resolves to the character string NULLFILE. This is equivalent to specifying DUMMY on a DD JCL statement.
 
Create 
large and 
extended format filesYou can create large and extended format files to store large amounts of data. Large and extended format data sets can have more than 65,535 tracks on a single volume. For more information about the characteristics and limitations associated with large and extended format files, refer to the appropriate IBM documentation.
Example
The following example defines models for work files that are used by the REORG utility.
CREATE DSMODEL W* DSN 'DBDC.TEMP.ZIP9.&DD'. UNIT SYSDA SPACE CYL (1000,100) BLKSIZE 8192; CREATE DSMODEL WD* FROM W* SPACE CYL (10, 10) VOLSER DBA001 UNIT 3390; CREATE DSMODEL WS* FROM W* SPACE CYL (3000, 10); REORG ...
By default, all work files are allocated on SYSDA devices with a 1000 cylinder initial space allocation, have a block size of 8192, and a data set name of "DBDC.TEMP.ZIP9.
xxxxxxx
", where 
xxxxxxx
 is the file's DDNAME. DBKEY files (those whose DDNAME begins with "WD") are allocated on volume DBA001 with an initial allocation of 10 cylinders. Sorted files (those whose DDNAME begins with "WS") have an initial allocation of 3000 cylinders.