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Compare Exchange in Cluster-Wide Session
-
Compare-Exchange items can be created and managed on the advanced session (
session.advanced)
Other options are listed in this compare-exchange overview. -
When working with compare-exchange items from the session,
the session must be opened as a cluster-wide session. -
In this page:
Create compare-exchange
Example
// The session must be first opened with cluster-wide mode
const session = documentStore.openSession({
transactionMode: "ClusterWide"
});
session.advanced.clusterTransaction.createCompareExchangeValue(
"Best NoSQL Transactional Database", "RavenDB" // key, value
);
await session.saveChanges();-
An
InvalidOperationExceptionexception is thrown when:- The session was Not opened as cluster-wide.
- The key already exists in the database.
Syntax
session.advanced.clusterTransaction.createCompareExchangeValue(key, item);| Parameters | Type | Description |
|---|---|---|
| key | string |
The compare-exchange item key. This string can be up to 512 bytes. |
| value | object |
The associated value to store for the key |
| Return value | Description |
|---|---|
object |
The new compare-exchange item is returned |
The compare exchange object returned
| Parameters | Type | Description |
|---|---|---|
| key | string |
The compare-exchange item key. This string can be up to 512 bytes. |
| value | object |
The value associated with the key |
| index | number |
Index for concurrency control |
Get compare-exchange
Get single value
await session.advanced.clusterTransaction.getCompareExchangeValue(key);| Parameters | Type | Description |
|---|---|---|
| key | string |
The key to retrieve |
| Return value | Description |
|---|---|
object |
The compare-exchange item is returned. Returns null if key doesn't exist. |
Get multiple values
await session.advanced.clusterTransaction.getCompareExchangeValues(keys);| Parameters | Type | Description |
|---|---|---|
| keys | string[] |
Array of keys to retrieve |
| Return value | Description |
|---|---|
Record<string, object> |
If a key doesn't exists the associate value will be null |
Get compare-exchange lazily
// Single item
const lazyItem = session.advanced.clusterTransaction.lazily.getCompareExchangeValue(key);
const item = await lazyItem.getValue();
// Multiple items
const lazyItems = session.advanced.clusterTransaction.lazily.getCompareExchangeValues(keys);
const items = await lazyItems.getValue();| Parameters | Type | Description |
|---|---|---|
| key | string |
The key to retrieve |
| keys | string[] |
Array of keys to retrieve |
Return value - after calling getValue |
Description |
|---|---|
object |
For single item: If the key doesn't exist it will return null |
Record<string, object> |
For multiple items: If a key doesn't exists the associate value will be null |
Delete compare-exchange
// Delete by key & index
session.advanced.clusterTransaction.deleteCompareExchangeValue(key, index);
// Delete by compare-exchange item
session.advanced.clusterTransaction.deleteCompareExchangeValue(item);| Parameters | Type | Description |
|---|---|---|
| key | string |
The key of the compare-exchange item to delete |
| index | number |
The index of this compare-exchange item |
| item | object |
The compare-exchange item to delete |
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