Table Writes

Update a Row by Key

UPDATE changes non-key cells for a matching key.

highlighted = computed this step

Update a row by key

UPDATE finds one row by key and changes named non-key cells.

find key, change value\text{find key, change value}

Apply the update

Applied writes are 1, and final row count stays 3.

applied=1\text{applied}=1

Write examples are tiny finite row modifications; SQL dialects, transactions, constraints beyond the visible key, triggers, indexes, concurrency, performance, and product behavior are out of scope.

Update a row by key: base tableidnamepoints1Ada102Ben203Cy15 writes in orderstepkindkeydetail0update2{points:25} write resultsstepkindkeystatusreasonbeforeafter0update2appliedok33 final tableidnamepoints1Ada102Ben253Cy15 write factsfactvaluebaseRowCount3writeCount1appliedCount1rejectedCount0finalRowCount3keyColumnidrowOrderkey

Read the changed cell

The matching row keeps its key and receives the new points value.

same key, changed cell\text{same key, changed cell}

Summary

This model does not update key columns.

key stays fixed\text{key stays fixed}