persistence

问题 Hey I'm learning this stuff, I don't really understand all of it and I have a problem, I don't know what to write in provider tag in persistence.xml Here are my persistence.xml and pom.xml files: pom.xml <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com

问题 Hey I'm learning this stuff, I don't really understand all of it and I have a problem, I don't know what to write in provider tag in persistence.xml Here are my persistence.xml and pom.xml files: pom.xml <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com

问题 What is the best way to store instances of a class to file/database? We have a base class called Command and loads of derived classes. Users create instances of these classes by adding commands to a graphical designer where they can configure them. (Set the properties). We then need a way to store these "commands" to a file without losing any information. One idea was to use db4o, but the GPL license is not acceptable for this project. Any suggestions or code samples? Update: (In order to "de

问题 I recently coded a simple telegram bot using the python-telegram-bot library, and deployed this bot on Heroku. Now i'm looking for an effective way to make the bot persistent, allowing it to store Bot_data and user_data between runs. I took a look at the persistence classes the library offers and i understood that PicklePersistence would not work with heroku's "ephemeral" hard drive. My question is, how can i implement the bot's persistence to make it work on heroku? Should i give up storing

问题 I recently coded a simple telegram bot using the python-telegram-bot library, and deployed this bot on Heroku. Now i'm looking for an effective way to make the bot persistent, allowing it to store Bot_data and user_data between runs. I took a look at the persistence classes the library offers and i understood that PicklePersistence would not work with heroku's "ephemeral" hard drive. My question is, how can i implement the bot's persistence to make it work on heroku? Should i give up storing

问题 I recently coded a simple telegram bot using the python-telegram-bot library, and deployed this bot on Heroku. Now i'm looking for an effective way to make the bot persistent, allowing it to store Bot_data and user_data between runs. I took a look at the persistence classes the library offers and i understood that PicklePersistence would not work with heroku's "ephemeral" hard drive. My question is, how can i implement the bot's persistence to make it work on heroku? Should i give up storing

问题 I'm breaking my head trying to find out what's wrong here. I'm working on a schema: It has a Story entity (table: stories) and I'm trying to add a column to this stories.portofoliotype_id which is a foreign key to PortfolioType (table: portofoliotypes) . I think I have the annotations right, I even logged MySQL queries, it gets the following query, which is correct. I'm trying to create a new story: insert into stories(backlog_id, description, iteration_id, name, parent_id,portfoliotype_id,

问题 Adding the following code to the AppDelegate will make the Firebase database available when the user is off-line: FIRDatabase.database().persistenceEnabled = true How can we make just some parts of the database available in off-line mode and some parts available just when the user is on-line? 回答1: Short answer: you can't . Firebase don't currently provide such a fine grained persistence scope API. What you can do instead is decrease/increase the amount of disk space used by the persistence

问题 We have a set of interfaces, used as an API, and referenced from other modules. A set of concrete implementations of those interfaces, private to the "main" app module. These classes carry a number of annotations (JPA as well as XStream for XML serialization). I've run into a problem. We have a user class which had a number of fields within it related to location. We'd like to roll those up into an Address class. We want the data (for now) to remain in the same table. The approach is an

问题 I have a relativley simple app which persists data to a plist file located in the documents folder. The data loads into a UITableView at startup. The user can then edit, delete or add records and any changes get saved back to the plist file. Now I would like to share this data (the plist file) across devices using iCloud. I have looked at the documentation and my understanding is that I need to create a UIDocument to "manage" the plist file. I have looked at several iCloud tutorials however