Using Data Dictionaries in Business Processes: Difference between revisions
New page: ==Why not direct file buffer access== In many cases, direct file buffer access would be simpler. But, it goes around your carefully constucted validation rules etc. Surely you can duplicat... |
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===Simple Example=== | ===Simple Example=== | ||
The simplest example is where we save new records in a table that does not have a parent file. | The simplest example is where we save new records in a table that does not have a parent file. | ||
<pre> | |||
Function CreateCustomer String sName String sEmail | Function CreateCustomer String sName String sEmail | ||
Handle hServer | Handle hServer | ||
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Function_Return iError | Function_Return iError | ||
End_Function | End_Function | ||
</pre> | |||
This save takes all the Data Dictionary rules into account that are linked to the validation and save mechanisms. So is much better than direct file access (using clear, move and saverecord).<br> | This save takes all the Data Dictionary rules into account that are linked to the validation and save mechanisms. So is much better than direct file access (using clear, move and saverecord).<br> | ||
But this simple example does not work if the record has a relationship to a parent table. It is also not using any field settings like capslock. | But this simple example does not work if the record has a relationship to a parent table. It is also not using any field settings like capslock. | ||
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===Relationships=== | ===Relationships=== | ||
When the record you wish to create has a relationship to a parent record, you have to first find the parent record, just like you do in a view, prior to issueing the save. Lets create inventory for an existing vendors. | When the record you wish to create has a relationship to a parent record, you have to first find the parent record, just like you do in a view, prior to issueing the save. Lets create inventory for an existing vendors. | ||
<pre> | |||
Function CreateInventoryItem Integer iVendor_ID String sItem_ID String sDescription | Function CreateInventoryItem Integer iVendor_ID String sItem_ID String sDescription | ||
Boolean bNotOk | Boolean bNotOk | ||
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Function_Return iError | Function_Return iError | ||
End_Function | End_Function | ||
</pre> | |||
This works nicely by finding the parent Vendor record, then create the new item. | This works nicely by finding the parent Vendor record, then create the new item. | ||
===Field Settings=== | ===Field Settings=== | ||
In the above example the Item_ID is not set to capslock. This is because the capslock is actually not part of the validation or save, it is a setting used by the dbForm and other visual objects. If we want to also apply these settings, we need to do some more. | In the above example the Item_ID is not set to capslock. This is because the capslock is actually not part of the validation or save, it is a setting used by the dbForm and other visual objects. If we want to also apply these settings, we need to do some more. | ||
Example required | Example required, checking the following Data Dictionary field property, from the Request_Validate function. | ||
Set Field_Options field Customer.Id to DD_CapsLock | |||
==Updating existing records== | ==Updating existing records== | ||
==Deleting records== | ==Deleting records== | ||
[[Category:Data Dictionaries]] | |||
Latest revision as of 04:50, 30 November 2007
Why not direct file buffer access
In many cases, direct file buffer access would be simpler. But, it goes around your carefully constucted validation rules etc. Surely you can duplicate these rules, but the whole idea of a Data Dictionary class is that the behaviour is inherited to all objects that initiate a record manipulation.
Saving new records
Simple Example
The simplest example is where we save new records in a table that does not have a parent file.
Function CreateCustomer String sName String sEmail
Handle hServer
Boolean bNotOk
Integer iError
Move (Customer_DD) To hServer
Send Clear of hServer
Set Field_Changed_Value Of hServer FIELD Customer.Name To sName
Set Field_Changed_Value Of hServer FIELD Customer.EMail_Address To sEmail
Get Request_Validate of hoServer to bNotOk
If (bNotOk) Move -1 To iError
Else Begin
Send Request_Save Of hServer
If (Err) Move -2 To iError
End
Function_Return iError
End_Function
This save takes all the Data Dictionary rules into account that are linked to the validation and save mechanisms. So is much better than direct file access (using clear, move and saverecord).
But this simple example does not work if the record has a relationship to a parent table. It is also not using any field settings like capslock.
Relationships
When the record you wish to create has a relationship to a parent record, you have to first find the parent record, just like you do in a view, prior to issueing the save. Lets create inventory for an existing vendors.
Function CreateInventoryItem Integer iVendor_ID String sItem_ID String sDescription
Boolean bNotOk
Integer iError
Send Clear of Invt_DD
// Find the parent record. This will also prime the foreign key (Invt.Vendor_ID)
Send Clear of Vendor_DD
Move iVendor_ID To Vendor.ID
Send Find to Vendor_DD Eq 1
// Set the other fields
Set Field_Changed_Value Of Invt_DD FIELD Invt.Item_ID To sItem_ID
Set Field_Changed_Value Of Invt_DD FIELD Invt.Description To sDescription
Get Request_Validate of Invt_DD to bNotOk
If (bNotOk) Move -1 To iError
Else Begin
Send Request_Save Of Invt_DD
If (Err) Move -2 To iError
End
Function_Return iError
End_Function
This works nicely by finding the parent Vendor record, then create the new item.
Field Settings
In the above example the Item_ID is not set to capslock. This is because the capslock is actually not part of the validation or save, it is a setting used by the dbForm and other visual objects. If we want to also apply these settings, we need to do some more.
Example required, checking the following Data Dictionary field property, from the Request_Validate function. Set Field_Options field Customer.Id to DD_CapsLock
