Struct PutStep
- Namespace
- DynaSharp
- Assembly
- DynaSharp.dll
A put in a transaction: what can follow it are its condition, the verbs of the next action, and sending. Attributes of an update do not exist here, so
.Add after .Put does not compile. See TransactWriteExtensions for the rest.
public readonly ref struct PutStep : ITransactWriteStep<PutStep>, ITransactWriteChain<PutStep>, IConditional<PutStep>, IRetryable<PutStep>- Implements
- Inherited Members
- Extension Methods
Methods
If(ExpressionHandler)
Adds a condition in the grammar of DynamoDB, for what the conditions of handles do not cover. An interpolated Attr stands for an attribute name and any other interpolated value for a value. If it does not hold, the whole transaction is cancelled, and a second condition means both must hold.
public PutStep If(ExpressionHandler condition)Parameters
conditionExpressionHandlerThe condition.
Returns
- PutStep
The step, which replaces this one.
If<TCondition>(TCondition)
Adds a condition. If it does not hold, the whole transaction is cancelled, and a second condition means both must hold.
public PutStep If<TCondition>(TCondition condition) where TCondition : IConditionParameters
conditionTConditionThe condition.
Returns
- PutStep
The step, which replaces this one.
Type Parameters
TConditionThe type of the condition.
Exceptions
- ArgumentNullException
conditionis null.
IgnoreVersion()
Writes the entity of this put without the check of its version, and still stores the next version, as a checked put does. Conditions of your own stay, and the other actions of the transaction are not touched. On a type without a VersionAttribute it changes nothing. See IgnoreVersion<T>(PutCommand<T>).
public PutStep IgnoreVersion()Returns
- PutStep
The step, which replaces this one.
Remarks
The version still advances. Every write of a versioned entity stores a new version, also one without the check: an update adds 1 to the stored version,
SET #v = if_not_exists(#v, :zero) + :one, so an item without one, or a new item, gets version 1, and a put or a batch stores the version of its entity plus one, as a checked put does. A writer
that holds a copy read before this write then fails with ConditionalCheckFailedException, or in a transaction with TransactionCanceledException, instead of overwriting it.
What this write itself overwrites is not checked: it wins over whatever another writer stored since, so it suits a change that does not depend on what was read, such as an Add to a counter.
MaxAttempts(int)
Sets the number of attempts of this call including the first, in place of MaxAttempts. A retry after a
lost response repeats a write that may have been applied, so 1 makes an ADD count at most once, and a lost response then reports a failure after the write was applied.
public PutStep MaxAttempts(int attempts)Parameters
attemptsintThe number of attempts.
Returns
- PutStep
The command, which replaces this one.
Exceptions
- ArgumentOutOfRangeException
attemptsis below 1.
ToRequestJson()
Renders the body this transaction would send, as DynamoDB JSON, without sending it. It ends the command, and is meant for tests and debugging. The text contains the items and a generated token that nothing ever sends.
public string ToRequestJson()Returns
- string
The request body.
Exceptions
- InvalidOperationException
The command was already sent, extended or rendered, or it has no action, which DynamoDB would reject.
Operators
implicit operator TransactWriteCommand(PutStep)
Hands the transaction on as a TransactWriteCommand, which is what a variable holds across a loop: tx = tx.Put(table, item).IfNotExists();. This uses the step up like
any call on it, so the command is the one handle left, and a clause of the action can no longer follow.
public static implicit operator TransactWriteCommand(PutStep step)Parameters
stepPutStepThe step, which this replaces.
Returns
Exceptions
- InvalidOperationException
The step was already sent, extended or rendered.