Table of Contents
Analyzing the structure of the original data set is most important when converting mainframe data sets to OpenFrame data sets. For the analysis, you need to create data set conversion schema file based on COBOL Copybooks or PL/I Include files.
This section describes the structure of schema file (v7.1) and other items required for data set conversion.
A schema file can be created by using the cobgensch, pligensch and sqlgensch tool.
There are two types of schemas: general schema and dynamic schema.
General Schema
* Schema Version 7.1 Label, Level, Field Name, Conversion Type, Sign Type, Length, Occurs, ODO Field * Condition Label, "Value", ( Label List )
Dynamic Schema
Includes Redefine Group ID and Redefine Element ID in addition to the items in a general schema. The following is the structure of a schema for dynamic conversion.
* Schema Version 7.1 - Dynamic conversion Label, Level, Field Name, Conversion type, Sign type, Length, Occurs, ODO Field, Redefine Group ID, Redefine Element ID * Condition Label, "Value", ( Label List )
For more information about the cobgensch, pligensch, sqlgensch tools, refer to OpenFrame Tool Reference Guide.
The schema file version created by using the latest OpenFrame/Base tool, sqlgensch, is not v7.1 and therefore cannot be used for migration.
The following describes each item of the schema structure.
| Item | Description |
|---|---|
Label | Unique field label. |
Level | Level of the field. |
Field Name | Name of the field. |
Conversion Type | Data type of the field. The following are the available data types.
|
Sign Type | Sign type defined in the COBOL SIGN IS clause for numeric data. The default is TRAILING. The following are the available sign types:
|
Length | Field length. |
Occurs | Occurrences of Occurs |
ODO Field | Field name that Occurs Depending On points to. |
Redefine Group ID | Group ID of REDEFINES clause. |
Redefine Element ID | ID of the element in the Redefine Group ID. |
The condition section in the schema file is generated by the $$COND statement in the Copybook. The $$COND statement structure is as follows:
$$COND : FIELD_01 : VALUE_01 (, VALUE02 … ) [: FIELD_02 : VALUE_03 (, VALUE04 ) … ] : REDEFINE_NAME [...]
When you use multiple 'FIELD_# : VALUE_#' conditions, each condition can be separated with a colon (:). In each field, you can compare multiple condition values (VALUE). If these conditions are satisfied, REDEFINES is executed.
For more information about the REDEFINES clause, refer to "3.5.3. Data Sets with REDEFINES Statements".
The following describes the structure of the Condition statement, which corresponds to $$COND statement in the schema file.
L#1, "VALUE_01" "VALUE02" … [, L#2, "VALUE_03" "VALUE04 … ], ( Label List )
| Item | Description |
|---|---|
Label(L#) | Label number of the field defined in REDEFINES statement. |
조건값(VALUE_#) | Values to compare with the field value of the label redefined in the REDEFINES statement. If a match is found, layout is created in the order of the label list. A field value of a label can be compared with multiple condition values connected with an OR. Condition statement of multiple labels can be compared with condition values separated by a comma (,). |
Label List | Label order list to use when the label field value meet the condition values. |
The ODO clause is an option that can be used to determine the OCCURS count by using other field values. The following Copybook shows an example of using the ODO option. The OCCURS count specified in the ODO clause represents the Min/Max value (if only one is specified, it is the Max value) and does not represent the actual number of repetitions. If ODO clause is not specified, the OCCURS count is set to 1 by default.
Currently, ODO can only be set on fields that are defined in the layout. The fields defined outside the layout cannot be set.
The following are sample COBOL Copybook with an ODO clause and schema file.
<COBOL Copybook>
01 ROOT.
03 AAA PIC X(1).
03 ODO OCCURS 10 DEPENDING ON AAA.
05 BBB PIC S9(2).
03 CCC PIC X(1) OCCURS 5.
<Schema File>
* Schema Version 7.1 L1, 01, ROOT, NULL, NULL, 0, 1:1, L2, 03, AAA, EBC_ASC, NULL, 1, 1:1, L3, 03, ODO, NULL, NULL, 0, 1:10, AAA L4, 05, BBB, ZONED, TRAILING, 2, 1:1, L5, 03, CCC, EBC_ASC, NULL, 1, 1:5, * Condition L0, "\0", ( L1 L2 L3 L4 L5 )
In this example, the condition statement that starts with L0 shows the default layout order list. For more information, refer to the following chapter.
You must specify conditions for a data set with a layout that includes a REDEFINES statement.
For more information about REDEFINES, refer to "3.5.3. Data Sets with REDEFINES Statements".
The following are sample COBOL Copybook with a REDEFINES statement and schema file.
<COBOL Copybook>
01 ROOT. 03 AAA PIC X(2). 03 BBB PIC X(3). 03 BBB-1 PIC S9(3) REDEFINES BBB. 03 CCC PIC X(3). 03 CCC-1 PIC 9(5) COMP-3 REDEFINES CCC. $$COND : AAA : "AB" : BBB-1 ( multiple redefines can be defined here!) $$COND : CCC : T"PACKED" : CCC-1
<Schema File>
* Schema Version 7.1 L1, 01, ROOT, NULL, NULL, 0, 1:1, L2, 03, AAA, EBC_ASC, NULL, 2, 1:1, L3, 03, BBB, EBC_ASC, NULL, 3, 1:1, L4, 03, BBB-1, ZONED, TRAILING, 3, 1:1, # REDEFINES BBB L5, 03, CCC, EBC_ASC, NULL, 3, 1:1, L6, 03, CCC-1, U_PACKED, NULL, 3, 1:1, # REDEFINES CCC * Condition L2, "AB", ( L1 L2 L4 L5 ) L5, T"PACKED", ( L1 L2 L3 L6 ) L0, "\0", ( L1 L2 L3 L5 )
In comparing the previous Copybook with the first condition line in the schema file, REDEFINES executes if L2 (Label2) matches the field name AAA and the field value is 'AB'. This creates a layout in the order of L1, L2, L4, and L5. According to the second condition, REDEFINES executes if L5 (Label5) matches the field name CCC and the field value is 'T"PACKED"'. This creates a layout in the order of L1, L2, L3, and L6. The last label L0 specifies the default layout order.
The condition values in the Condition section of the schema file that corresponds to the $$COND statement in the Copybook can be defined with multiple types. This allows you to convert the field type as needed by specifying the field type before the opening quotation mark (") that enclose the condition value.
The following are available field types.
| Type | Description |
|---|---|
! (exclamation mark) | Checks NOT EQUALITY. |
'(empty)' | Returns the default type of the field. |
'A' | Uses the ASCII character of the value. |
'E' | Converts to EBCDIC character. |
'P' or 'UP' | Converts to Packed Decimal or Unsigned Packed Decimal type. |
'Z' or 'UZ' | Converts to Zoned Decimal or Unsigned Zoned Decimal type. |
'G' | Converts to GRAPHIC (2Byte) character. |
'H' | Coverts the value to a Hexadecimal value. (Example: H"123" → 0x7B) |
'X' | Converts the 2 byte value to a 1 byte Hex value. (Example: X"12AB" → 0x12 0xAB) |
'T' | Checks the field type. Only Zoned and Packed are supported. (Example: T"ZONED"/T"PACKED" → Check whether the field is Zoned/Packed Decimal.) |
For more information about condition value (VALUE) types, refer to "3.5.3. Data Sets with REDEFINES Statements".