Session
A Session instance is used for handling the connection and sending queries through the connection. In a single session, multiple queries will be executed serially. In order to execute parallel queries, multiple sessions are required.
Method Summary
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beginTransaction(transactionConfig: TransactionConfig): TransactionPromise Begin a new transaction in this session. |
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close(): Promise Close this session. |
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executeRead(transactionWork: function(tx: ManagedTransaction): Promise, transactionConfig: TransactionConfig): Promise Execute given unit of work in a READ transaction. |
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executeWrite(transactionWork: function(tx: ManagedTransaction): Promise, transactionConfig: TransactionConfig): Promise Execute given unit of work in a WRITE transaction. |
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lastBookmarks(): string[] Return the bookmarks received following the last completed Transaction. |
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run(query: mixed, parameters: Object, transactionConfig: TransactionConfig, parameterRules: Rules): Result Run Cypher query
Could be called with a query object i.e.: |
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Public Methods
public [Symbol.asyncDispose]() source
public beginTransaction(transactionConfig: TransactionConfig): TransactionPromise source
Begin a new transaction in this session. A session can have at most one transaction running at a time, if you want to run multiple concurrent transactions, you should use multiple concurrent sessions.
While a transaction is open the session cannot be used to run queries outside the transaction.
Params:
| Name | Type | Attribute | Description |
| transactionConfig | TransactionConfig |
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Configuration for the new auto-commit transaction. |
public executeRead(transactionWork: function(tx: ManagedTransaction): Promise, transactionConfig: TransactionConfig): Promise source
Execute given unit of work in a READ transaction.
Transaction will automatically be committed unless the given function throws or returns a rejected promise.
Some failures of the given function or the commit itself will be retried with exponential backoff with initial
delay of 1 second and maximum retry time of 30 seconds. Maximum retry time is configurable via driver config's
maxTransactionRetryTime property in milliseconds.
NOTE: Because it is an explicit transaction from the server point of view, Cypher queries using "CALL {} IN TRANSACTIONS" or the older "USING PERIODIC COMMIT" construct will not work (call Session#run for these).
Params:
| Name | Type | Attribute | Description |
| transactionWork | function(tx: ManagedTransaction): Promise | Callback that executes operations against a given Transaction. |
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| transactionConfig | TransactionConfig |
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Configuration for all transactions started to execute the unit of work. |
Return:
| Promise | Resolved promise as returned by the given function or rejected promise when given function or commit fails. |
public executeWrite(transactionWork: function(tx: ManagedTransaction): Promise, transactionConfig: TransactionConfig): Promise source
Execute given unit of work in a WRITE transaction.
Transaction will automatically be committed unless the given function throws or returns a rejected promise.
Some failures of the given function or the commit itself will be retried with exponential backoff with initial
delay of 1 second and maximum retry time of 30 seconds. Maximum retry time is configurable via driver config's
maxTransactionRetryTime property in milliseconds.
NOTE: Because it is an explicit transaction from the server point of view, Cypher queries using "CALL {} IN TRANSACTIONS" or the older "USING PERIODIC COMMIT" construct will not work (call Session#run for these).
Params:
| Name | Type | Attribute | Description |
| transactionWork | function(tx: ManagedTransaction): Promise | Callback that executes operations against a given Transaction. |
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| transactionConfig | TransactionConfig |
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Configuration for all transactions started to execute the unit of work. |
Return:
| Promise | Resolved promise as returned by the given function or rejected promise when given function or commit fails. |
public lastBookmarks(): string[] source
Return the bookmarks received following the last completed Transaction.
Return:
| string[] | A reference to a previous transaction. |
public run(query: mixed, parameters: Object, transactionConfig: TransactionConfig, parameterRules: Rules): Result source
Run Cypher query
Could be called with a query object i.e.: {text: "MATCH ...", parameters: {param: 1}}
or with the query and parameters as separate arguments.
This is an auto-commit query, meaning the server will commit the results without further input.
The transaction is guaranteed to be committed anywhere between the start of it (i.e., calling Session#run) and fully consuming the returned Result. The Result can be consumed as a promise or lazily using Result#subscribe.
If the code moves on (i.e., by calling Session#close or by starting another session) before the Result is fully consumed, it will be consumed in the background. However, in this case any error that occurs will be swallowed silently. Therefore, it is reccomended to always fully consume Results from Session.run.
Params:
| Name | Type | Attribute | Description |
| query | mixed | Cypher query to execute |
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| parameters | Object | Map with parameters to use in query |
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| transactionConfig | TransactionConfig |
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Configuration for the new auto-commit transaction. |
| parameterRules | Rules |
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Rules to typecheck and/or map the parameter object. Must not be provided as a separate argument if an Object is passed as first argument |