Managing file groups: Difference between revisions
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== Permanent, Temporary and Ad-hoc Groups == | == Permanent, Temporary and Ad-hoc Groups == | ||
===CREATE GROUP command=== | |||
<p>File groups are created using the CREATE GROUP command. The types of groups are:</p> | |||
<table> | |||
<tr class="head"> | |||
<th>Type of group</th> | |||
<th>Created...</th> | |||
</tr> | |||
<tr> | |||
<td>Permanent </td> | |||
<td> | |||
<p>By the system manager using the CREATE command.</p> | |||
<p>User access is determined by the privileges defined for the file group.</p> | |||
<p>Use the following syntax to create a permanent group: </p> | |||
<p class="code">CREATE PERM GROUP groupname | |||
FROM {filename [AT location] [(OPTIONAL) | (MANDATORY)]} ,... [PARAMETER parameter[=value] [PARAMETER parameter[=value]]... | |||
. | |||
. | |||
. | |||
END | |||
</p> | |||
<p>For information about creating permanent groups, see the Rocket <var class="product">Model 204</var> Parameter and Command Reference. </p> | |||
</td> | |||
</tr> | |||
<tr> | |||
<td>Temporary</td> | |||
<td> | |||
<p>By an individual user with the CREATE command and can be referenced only by that user. </p> | |||
<p>Temporary group names exist only during the current login session and are deleted automatically when you log out, unless you delete them during the session. </p> | |||
<p>Use the following syntax to create a temporary group:</p> | |||
<p class="code">CREATE [TEMP] GROUP groupname FROM filename | |||
[,filename ...][PARAMETER parameter_list] | |||
. | |||
. | |||
. | |||
END | |||
</p> | |||
<p>The parameters available for temporary file groups are discussed in the Rocket <var class="product">Model 204</var> Parameter and Command Reference.</p> | |||
</td> | |||
</tr> | |||
<tr> | |||
<td>Ad hoc</td> | |||
<td> | |||
<p>Within a User Language request by prefacing a statement with the clause: </p> | |||
<p class="code">IN <var class="term">file1</var>, <var class="term">file2</var> [,<var class="term">file3</var> ...] | |||
</p> | |||
<p>Ad hoc groups have no name and exist only for the current request. They allow record retrieval from many files at once without defining a group in advance. As in any IN clause, all of the files in an ad hoc group must be opened before the group is mentioned. For more information, see the description of Ad hoc groups in the <var>Rocket Model 204 User Language Manual</var>.</p> | |||
</td> | |||
</tr> | |||
</table> | |||
=== Permanent Groups === | === Permanent Groups === | ||
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=== Temporary Groups === | === Temporary Groups === | ||
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=== Ad-hoc Groups === | === Ad-hoc Groups === | ||
== Using Groups == | == Using Groups == | ||
Revision as of 23:26, 25 April 2013
Overview
Permanent, Temporary and Ad-hoc Groups
CREATE GROUP command
File groups are created using the CREATE GROUP command. The types of groups are:
| Type of group | Created... |
|---|---|
| Permanent |
By the system manager using the CREATE command. User access is determined by the privileges defined for the file group. Use the following syntax to create a permanent group: CREATE PERM GROUP groupname FROM {filename [AT location] [(OPTIONAL) | (MANDATORY)]} ,... [PARAMETER parameter[=value] [PARAMETER parameter[=value]]... . . . END For information about creating permanent groups, see the Rocket Model 204 Parameter and Command Reference. |
| Temporary |
By an individual user with the CREATE command and can be referenced only by that user. Temporary group names exist only during the current login session and are deleted automatically when you log out, unless you delete them during the session. Use the following syntax to create a temporary group: CREATE [TEMP] GROUP groupname FROM filename [,filename ...][PARAMETER parameter_list] . . . END The parameters available for temporary file groups are discussed in the Rocket Model 204 Parameter and Command Reference. |
| Ad hoc |
Within a User Language request by prefacing a statement with the clause: IN file1, file2 [,file3 ...] Ad hoc groups have no name and exist only for the current request. They allow record retrieval from many files at once without defining a group in advance. As in any IN clause, all of the files in an ad hoc group must be opened before the group is mentioned. For more information, see the description of Ad hoc groups in the Rocket Model 204 User Language Manual. |
Permanent Groups
Temporary Groups
Ad-hoc Groups
Using Groups
Files with large numbers of record
Postponing reorganizations with Groups
Note: the following technique cannot be used if there are references in your code to Internal Record Numbers (IRNs)
File X is almost full Define File Y, which looks like File X (same field names) File Y can be defined to have whatever table sizes it needs Group File X and Y together, with File Y as UPDTFILE Run your application against grouped files X and Y Example: CREATE PERM GROUP X FROM X, Y� PARAMETER UPDTFILE = Y� END