_TL, _VL, _ALL, _B, _F, _S tables in Oracle Apps

_ALL: These are Multi-org tables where we can see data for all operating units.
Ex: oe_order_headers_all, oe_order_lines_all, po_headers_all ap_supplier_sites_all

_TL:
These are translated tables which have the translated value for each installed language. These are tables corresponding to another table with the same name minus the TL. 
These tables provide multiple language support. 
For each item in the table without TL there can be many rows in the _TL table, but all with different values in the LANGUAGE column.
Ex: fnd_responsibility_tl, oe_transaction_types_tl

_F
These are date tracked tables which occur in HR and Payroll. In these tables there are two date columns EFFECTIVE_START_DATE and EFFECTIVE_END_DATE which together with the PK identifies a row uniquely. The date intervals cannot overlap.
Ex: per_all_people_f, per_all_assignments_f

_B
These are the BASE tables. 
They are very important and the data is stored in the these table with all validations.
It is supposed that these table will always contain the perfect format data.
If anything happens to the BASE table data, then it is a data corruption issue.
Ex: mtl_system_items_b

_V are views.

_VL
These are views for multi language tables which combines the row of the base table with the corresponding row of the _TL table where the LANGUAGE = USERENV('LANG'). 

_S are sequences, used for generating new values for the primary key of a table.

Advanced Supply Chain Planning (ASCP)

MRP:ATP Database Link is the profile option in Source instance which determines the database link to be used to connect to Planning Server.

In a distributed installation where EBS Source instance is release 12.1, we must have the responsibility APS COLLECTIONS on the source instance to run collections and APS RELEASE on the source instance to release planned orders.

Item Validation Organization:

Navigation: Order Management > Setup > System Parameters > Values

•  Item Validation Organization system parameter is the key parameter which should be defined with out which items cannot be placed on Sales orders.
• While entering Sales Orders, Order Management validates if the item is orderable in the organization specified as Item Validation Organization. It does not validate against the organization / warehouse specified on Sales Order.
• Only items that have "Customer Orders Enabled" item attribute set to Yes in Item Validation Organization will appear in the item LOV on sales order line.