View source for Adding records (File architecture)

==Adding a record to a file==
<p>This section describes the process to add a record to a Model 204 file. It presumes that the fikle has already been [[CREATE command: File|CREATE]]d and [[INITIALIZE command|INITIALIZE]]d, and that all fields and Repeating Field Groups (RFGs) needed in this action are defined to the file. </p>
<p>And a reminder: while fields and RFGs may, generally, be added to the file at any time, some field attributes (for example, the pre-allocation of fields with the OCCURS attribute), may only be added in a file to which no data has yet been added.</p>

<p>The addition of the record is driven by the User Language [[Data Maintenance#STORE RECORD statement|STORE RECORD statement]] with an (optional) list of ''fieldname'' value pairs, as in the following example. </p>

<p class="code">STREC: STORE RECORD
  NAME=RASPUTIN
  SEX=MALE
  OCCUPATION=MONK
 END STORE
</p>
<p>Alternatively, you can use the Host Language Interface IFBREC, IFPUT, and IFSTORE functions, which also require a list of name = value pairs.</p>
<p>All referenced field names must previously have been defined, but not all field names need to have assigned values in every record. In fact, if you omit a field, the field is not stored in the record at all, thus saving space in the file.</p>
<p>For more information see the Rocket <var class="product">Model&nbsp;204</var> User Language Manual or the Rocket <var class="product">Model&nbsp;204</var> Host Language Interface Reference Manual.</p>

==How Model 204 adds records to a file==
<p>The process of adding a new record to a file, <var class="product">Model&nbsp;204</var> is as follows:</p>
#Like all User Language code, the process consists of two parts; first the code is compiled: 
##all field names, the values of coded fields and some FRV fields are converted into fixed-length codes from Table A
##all other attributes of the referenced fields are noted for use during the execution
#Presuming the code compiles, in the evaluation process, when the STORE RECORD statement is executed: 
##a physical internal record number (IRN) is assigned in Table B taking the [[BRESERVE parameter]] into account
##if there are any preallocated fields, the fields in the [[#Table D (File Architecture) Record Map|record map]] are added to the record
##then, for each field value pair in the STORE RECORD statement (none are required, an 'empty' record can be created if no fields are referenced): 
###the field value pair is added to the record (or preallocated field updated)
###of course, normal extension record rules apply (as discussed in [[Table B (File Architecture)|Table B]])
###if the field is indexed, the necessary updates occur to Tables C and D.

==Considerations when adding many records to a file==
<p>If you are adding a large number of records to a file, consider these alternatives for increased efficiency: </p>
<ul>
<li>Deferred updates. Defer changes or additions that update Tables C and D, instead specifying that step 3 above be performed in separate phases. [[ Deferred Update Feature#Deferred Update Feature|Deferred Update Feature]] describes how to use deferred updates.</li>
<li>File Load utility. If the raw data for the records to be stored in the <var class="product">Model&nbsp;204</var> file already exists in a machine-readable format (magnetic tape, direct-access storage, cards), use the File Load utility to load that data directly into the <var class="product">Model&nbsp;204</var> file quickly and economically. [[ File Load Utility#File Load Utility|File Load Utility]] describes the File Load utility.</li>
</ul>
<p>&nbsp;</p>
[[Category:File architecture]]