I want to use Accounts in my CorDapp and I would like to check if an account already exists before creating a new one.
How can I query the Vault to see if an account with a specific name exists or not?
int numberOfResults = getServiceHub().cordaService(KeyManagementBackedAccountService.class)
.accountInfo("USER_NAME").size();
Btw, this service KeyManagementBackedAccountService has a lot of useful functions; it comes with the Accounts library. I recommend exploring it.
Related
In the Corda accounts library, in order to change the host "ownership" of the account from one node to another, one would need to change the Host in the AccountInfo state to the new host (node), along with share all vault states relevant to this account.
AccountInfo doesn't have an Update command (AccountInfo commands), meaning you cannot change the host once it is created.
Has this feature been excluded for any reason? Are there any plans to introduce an Update command (with supporting flows)?
What steps would be involved in a move/transfer (host ownership)? And what are the potential caveats around this implementation?
Amol there will be work done on this in the future but as of now, there are two options which could help you resolve your issue.
Set up a new account on the new node. Generate new key(s) for the new account. Spend all the states from the old account to this new account.
If you control the all the keys used to participate in your states and can migrate them to the new node then you just need to import the key pairs somehow and then copy all the states across from the old node to the new node.
Hope that helps.
Context: We are trying to load some CSV format data into GCP BigQuery using GCP Dataflow (Apache Beam). As a part of this for the first time (for each table) creating the BQ tables thru BigQueryIO API. One of the customer requirement is the data on GCP needs to be encrypted using Customer supplied/managed Encryption keys.
Problem Statement: We are not able to find any way to specify the "Custom Encryption Keys" thru APIs while creating Tables. The GCP documentation details about how to specify the Custom encryption keys thru GCP BQ Console but could not find anything for specifying it thru APIs from within DataFlow Code.
Code Snippet:
String tableSpec = new StringBuilder().append(PipelineConstants.PROJECT_ID).append(":")
.append(dataValue.getKey().target_dataset).append(".").append(dataValue.getKey().target_table_name)
.toString();
ValueProvider<String> valueProvider = StaticValueProvider.of("gs://bucket/folder/");
dataValue.getValue().apply(Count.globally()).apply(ParDo.of(new RowCount(dataValue.getKey())))
.apply(ParDo.of(new SourceAudit(runId)));
dataValue.getValue().apply(ParDo.of(new PreProcessing(dataValue.getKey())))
.apply(ParDo.of(new FixedToDelimited(dataValue.getKey())))
.apply(ParDo.of(new CreateTableRow(dataValue.getKey(), runId, timeStamp)))
.apply(BigQueryIO.writeTableRows().to(tableSpec)
.withSchema(CreateTableRow.getSchema(dataValue.getKey()))
.withCustomGcsTempLocation(valueProvider)
.withCreateDisposition(BigQueryIO.Write.CreateDisposition.CREATE_IF_NEEDED)
.withWriteDisposition(BigQueryIO.Write.WriteDisposition.WRITE_APPEND));
Query: If anybody could let us know
If this is possible to provide encryption key thru Beam API?
If its not possible with the current version what could be the possible work
around?
Kindly let know if additional information is required.
Customer supplied encryption keys is a new feature, not all libraries have been updated to support it yet.
If you know the table name in advance, you can use UI/CLI or API to create table, then run your normal flow to load data into that table. That might be a work around for you.
https://cloud.google.com/bigquery/docs/customer-managed-encryption#create_table
API to create table: https://cloud.google.com/bigquery/docs/reference/rest/v2/tables/insert
You need to set this section on table object:
"encryptionConfiguration": {
"kmsKeyName": string
}
More details on table: https://cloud.google.com/bigquery/docs/reference/rest/v2/tables#resource
How to create data base link in oracle 11 g to Access Tables.
You seem to have copied the example in the documentation without really understanding it.
The USING 'local' part of the statement is creating a link to 'the local database', where local is the service name of a database. (The example is a bit confusing, to be fair).
When the link is used it tries to interpret local as a service name, appending the current database's domain, as the docs say:
USING 'connect string'
Specify the service name of a remote database. If you specify only the
database name, then Oracle Database implicitly appends the database
domain to the connect string to create a complete service name.
Therefore, if the database domain of the remote database is different
from that of the current database, then you must specify the complete
service name.
If you're trying to create a link back into the same database - which would be a bit odd but I've seen it done in place of grant access across schemas, and that seems to be what the example is hinting at - then you can replace 'local' in the USING clause with the service name of your current database (e.g. USING 'orcl', or whatever).
You can also use a TNS alias; if your tnsnames.ora has an entry for SOME_DB which points to the SID or service name of another database, you can have USING'some_db'`. You should be able to use any connect string I think; certainly Easy Connect is allowed. There's more in the net services admin guide.
Could someone please explain how to obtain a list of all existing databases on a PostgreSQL server, to which the user already has access, using Qt? PostgreSQL documentation suggests the following query:
SELECT datname FROM pg_database WHERE datistemplate = false;
What are the correct parameters to the following functions:
QSqlDatabase::setDatabaseName(const QString & name) //"postgres" or "pg_database"?
QSqlDatabase::setUserName(const QString & name) //actual user name?
QSqlDatabase::setPassword(const QString & password) //no password? or user password?
Much appreciated. Thank you in advance.
You appear to have already answered the first part of your question. Connect to the postgres or template1 database and issue the query you've quoted above to get a list of databases. I'm guessing - reading between the lines - that you don't know how to connect to PostgreSQL to send that query, and that's what the second part of your question is about. Right?
If so, the QSqlDatabase accessor functions you've mentioned are used to set connection parameters, so the "correct" values depend on your environment.
If you want to issue the query above - to list databases - then you would probably want to connect to the postgres database as it always exists and isn't generally used for anything specific, it's there just to be connected to. That means you'd call setDatabaseName("postgres");. Passing pg_database to setDatabaseName would be nonsensical, since pg_database is the pg_catalog.pg_database table, it isn't a database you can connect to. pg_database is one of those odd tables that exists in every database, which might be what confused you.
With the other two accessors specify the appropriate username and password for your environment, same as you'd use for psql; there's no possible way I could tell you which ones to use.
Note that if you set a password but one isn't required because authentication is done over unix socket ident, trust, or other non-password scheme the password will be ignored.
If this doesn't cover your question, consider editing it and explaining your problem in more detail. What've you tried? What didn't work how you expected? Error messages? Qt version?
When we developers write data access code what should we really worry about if the application should scale well and handle the load / Hits.
Given this simple problem , how would you solve it in scalable manner.
1.ProjectResource is a Class ( Encapsulating resources assigned to a Project)
2.Each resource assigned to Project is User Class
3.Each User in the Project also has ReportingHead and ProjectManager who are also instance of User
4.Finally there is a Project class containing project details
Legend of classes used
User
Project
ProjectResource
Table Diagram
ProjectResource
ResourceId
ProjectId
UserId
ReportingHead
ProjectManager
Class Diagram
ProjectResource
ResourceId : String / Guid
Project : Project
User : User
ReportingHead : User
ProjectManager : User
note:
All the user information is stored in the User table
All the Project information is stored in the project table
Here's the Problem
When the application requests for Resource In a Project operations below are followed
First Get the Records for the Project
Get the UserId , make the request(using Users DAL) to get the user instance
Get the ProjectId, make the request(using Projects DAL) to get the project information
Finally assign Users and Project to instance of ProjectResource
clearly you can see 3 Db Calls are made here for populating single ProjectResource but the concerns and who manages the objects are clearly defined. This is the way i have planned to , since there is also connection pooling available in Sql Server & ADO.net
There is also another way where all the details are retrieved in single hit using Table Inner Joins and then Populating.
Which way should i really be taking and Why?
Extras:
.NET 2.0,ASP.net 2.0,C#,Sql Server 2005,DB on same machine hosting application.
For best performance and scalability, you should minimize the number of round-trips to the DB. To prove that to yourself, just run some benchmarks; it becomes clear very quickly.
One approach to a single round-trip is to use joins. Another is to return multiple result sets. The latter can be helpful in eliminating possible duplicate data.