The client of the table this transaction writes to
Merges a consumer's write-condition guard onto its row.
The guard's condition is parenthesized and ANDed onto the item queued on the row, or onto a new ConditionCheck requiring the row's existence when nothing is queued there. The item returns the row it failed on, so a cancellation can be attributed.
Call only in an operation that carries a condition, after every library item is queued: an item queued later onto a guard-only row throws.
The row the guard checks
The guard
Merges a library equality pin onto its row, the same way as addGuard. The pin is compiled here, so the expression and the check run against a returned row on cancellation can never disagree.
The row the pin checks
The pin
Execute the transaction
Returns a value placeholder prefix no other fragment or pin of this
transaction uses (EX: wc1_), for compiling one condition fragment. A
filter builder numbers placeholders from zero per instance, so two
fragments compiled separately would otherwise bind the same placeholder
Replaces the tracked condition-failure message for an already-queued update item, for conditions appended to the item after it was queued
The queued update item, matched by reference
The replacement error message
Build and executes a TransactWriteItems request
Write-condition guards and library pins are merged onto the item already queued on their row (TransactionBuilder.addGuard, TransactionBuilder.addPin), after every library item is queued. A transaction with neither sends exactly the items queued.