Question
Morgan Stanley
IN
Last activity: 1 Jun 2016 4:53 EDT
Difference between internal, external tables
When do we call a table as an external table and internal table?
What columns differentiate an external table and internal table and how many minimum OOTB properties should be present to call it internal.
Accepted Solution
Tetrasoft India Private Limited
IN
As per my understanding, for the external mapping, if PRPC says that you can use the Obj- methods then you don't need to map any external columns as long as the column names and properties are the same. PRPC is smart enough to automatically map the columns to the properties where the name matches.
In general, we use mapping wizard for external class mapping :
https://docs-previous.pega.com/how-map-external-database-table-class
Here are a few details I found regarding external class :
An external class is a concrete class (instance of the Rule-Obj-Class rule type) that corresponds to a table in an external relational database, rather than to a table or view in the PegaRULES database.
No inheritance or rule resolution applies to external classes, even if the class name contains a dash character.
Each external class has an associated database table instance (Data-Admin-DB-Table class) and so cannot be part of a class group.
These methods can operate on an instance of an external class:
As per my understanding, for the external mapping, if PRPC says that you can use the Obj- methods then you don't need to map any external columns as long as the column names and properties are the same. PRPC is smart enough to automatically map the columns to the properties where the name matches.
In general, we use mapping wizard for external class mapping :
https://docs-previous.pega.com/how-map-external-database-table-class
Here are a few details I found regarding external class :
An external class is a concrete class (instance of the Rule-Obj-Class rule type) that corresponds to a table in an external relational database, rather than to a table or view in the PegaRULES database.
No inheritance or rule resolution applies to external classes, even if the class name contains a dash character.
Each external class has an associated database table instance (Data-Admin-DB-Table class) and so cannot be part of a class group.
These methods can operate on an instance of an external class:
- Obj-Browse
- Obj-Open
- Obj-Open-by-Handle C
- Obj-Delete
- Obj-Refresh-and-Lock
- Obj-Save
- Obj-Save-Cancel
- Commit
- Rollback
You can't create Declare Index rules which have an external class as the Applies To key part.
In some cases, no single property in the external class can serve as a unique handle. To support the Obj-Open-by-Handle method with external classes, PRPC assembles a substitute string from the key columns of the table.
Also, It is preferable to have tables as internal ones because the extra columns (particularly pxObjClass) can prove very useful in processing.
Coforge DPA
IN
A table which has the two columns pxObjClass and pzpvStream called internal tables and those who dont have these two are called as external tables.
Morgan Stanley
IN
Thanks prathap.
I was actually trying to understand what db columns are necessary to term a table internal.
Below is one such table which does not have pzpvstream and i'm really confused as to what columns prpc has looked into and called it internal
Morgan Stanley
IN
I have removed pxobjclass and observed the test connection shows the table as external..
Despite adding pzpvstream it still shows as external.
Would there be any difference in the way PRPC sees the tables which are internal/external.. In the way the data is retried/inserted/updated etc...?
Tetrasoft India Private Limited
IN
Hi Avinash,
A table which has the pxObjClass and pzInskey columns is called an internal table and the table which doesn't have these two (pxObjClass and pzInskey) columns are called as external tables
Morgan Stanley
IN
Thanks Swati.
Either its external or internal its just a table.. Would there be any difference in the way PRPC treats these entities? or would they be seen as just tables mapped to classes.
Accepted Solution
Tetrasoft India Private Limited
IN
As per my understanding, for the external mapping, if PRPC says that you can use the Obj- methods then you don't need to map any external columns as long as the column names and properties are the same. PRPC is smart enough to automatically map the columns to the properties where the name matches.
In general, we use mapping wizard for external class mapping :
https://docs-previous.pega.com/how-map-external-database-table-class
Here are a few details I found regarding external class :
An external class is a concrete class (instance of the Rule-Obj-Class rule type) that corresponds to a table in an external relational database, rather than to a table or view in the PegaRULES database.
No inheritance or rule resolution applies to external classes, even if the class name contains a dash character.
Each external class has an associated database table instance (Data-Admin-DB-Table class) and so cannot be part of a class group.
These methods can operate on an instance of an external class:
As per my understanding, for the external mapping, if PRPC says that you can use the Obj- methods then you don't need to map any external columns as long as the column names and properties are the same. PRPC is smart enough to automatically map the columns to the properties where the name matches.
In general, we use mapping wizard for external class mapping :
https://docs-previous.pega.com/how-map-external-database-table-class
Here are a few details I found regarding external class :
An external class is a concrete class (instance of the Rule-Obj-Class rule type) that corresponds to a table in an external relational database, rather than to a table or view in the PegaRULES database.
No inheritance or rule resolution applies to external classes, even if the class name contains a dash character.
Each external class has an associated database table instance (Data-Admin-DB-Table class) and so cannot be part of a class group.
These methods can operate on an instance of an external class:
- Obj-Browse
- Obj-Open
- Obj-Open-by-Handle C
- Obj-Delete
- Obj-Refresh-and-Lock
- Obj-Save
- Obj-Save-Cancel
- Commit
- Rollback
You can't create Declare Index rules which have an external class as the Applies To key part.
In some cases, no single property in the external class can serve as a unique handle. To support the Obj-Open-by-Handle method with external classes, PRPC assembles a substitute string from the key columns of the table.
Also, It is preferable to have tables as internal ones because the extra columns (particularly pxObjClass) can prove very useful in processing.