Data storage in base table and extended table

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Vipin Verma3
Tera Contributor

‎09-16-2023 12:19 PM

When a table is extended, it inherits all the columns from the table it is extending. When we store data in extended table, records are created in base table as well. My question is on the data stored for columns that are in the base table. The data is only stored in the base table, or it is stored both in base table and extended table? 

 

If data is stored in both tables base and extended, then what is the reason of keeping the data in both tables?

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Bert_c1
Kilo Patron

‎09-16-2023 02:26 PM

And if you are interested in how Servicenow Database Schema design works on popular parent tables (task and cmdb) see:

 

Table Extensions and Classes

 

SQL Joins are used to link parent-child table records.  And for tables where there are "lots" of records and child tables, database performance suffers the more Joins are used to access the records.

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WillieW
Tera Expert
In response to anchaljha24

a week ago

check the records in the sys_storage_alias table.  Also records in the sys_stoage_table_alias to see how fields at tables are stored in the database.

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