Prerequisites for SQL access to CODASYL definitions

In order for a CODASYL subschema to be processed on a completely relational basis with SQL it must satisfy the following conditions:

Condition	SQL limitation if the condition is not satisfied
The temporary realm must be present.	No SQL access permitted.
All sets whose member record types are included in the subschema must likewise be included in the subschema.	No SQL access permitted for the record type involved.
All ASCENDING/DESCENDING/CALC and SEARCH keys must be completely contained in the subschema.	No SQL access permitted for the record type involved.
Sets may not be defined with ORDER IS NEXT or ORDER IS PRIOR.	Neither INSERT nor UPDATE permitted for the member record type of the set.
Record types may not be distributed among multiple realms.	INSERT not permitted for the record type involved.
A record type may not be defined with LOCATION MODE IS DIRECT or DIRECT-LONG	INSERT not permitted for the record type involved.
A record type may not be defined with the SSL clause COMPRESSION.	UPDATE not permitted for the record type involved.
A record type may not contain variable length fields.	No SQL access permitted for the record type involved.
A record type may not contain a national item (Unicode).	No SQL access permitted for the record type involved.
A record type may not include packed or unpacked numerical fields for which the following apply with respect to the number of storage locations and the scale factor: number of storage locations > 15 or scale factor < 0 or scale factor > number of storage locations A positive scale factor gives the number of positions to the right of the decimal point. A negative scale factor specifies how many zeroes UDS/SQL must add to the field contents when performing calculations.	No SQL access permitted for the field involved, and no INSERT permitted for the record type involved.

Table 13: Prerequisites for SQL access