How to rename columns in ORMLite?

问题

How can we rename column name in ORMLite?

I am trying to write that query SELECT id as _id from some_table

Android Cursor Adapter requires us to have column named _id and ORMLite requires us to have column named id.

I am trying to write that query and return Cursor from this query.

Dao<NewsArticle, Long> newsArticleDao =
       ((SomeApp)mContext.getApplicationContext()).getDAOConnection().getDAO(
            NewsArticle.class);

QueryBuilder<NewsArticle, Long> query = newsArticleDao.queryBuilder().selectRaw(
      "`id` as `_id`");
PreparedQuery<NewsArticle> preparedQuery = query.prepare();

CloseableIterator<NewsArticle> iterator = newsArticleDao.iterator(preparedQuery);

AndroidDatabaseResults results =
        (AndroidDatabaseResults)iterator.getRawResults();
cursor = results.getRawCursor();

That's what I have so far but I am getting this error when I pass query to iterator.

java.sql.SQLException: Could not compile this SELECT_RAW statement since the caller is expecting a SELECT statement. Check your QueryBuilder methods.

回答1:

I guess I have to answer my question.

I still couldn't figure out how to rename column but I found the solution to problem.

Android Custom Adapter requires column named_id that's true but ORMLite doesn't require the column name to be id, I was wrong about that. It wants you to mark a column as id.

In my model, I marked my id and now it works like a charm.

 @DatabaseField(id = true)
 private long _id;

回答2:

How can we rename column name in ORMLite?

Not sure I understand what you mean by rename. I don't think you mean schema change here. Are you talking about how to assign the name of the field in the database? You can do:

@DatabaseField(id = true, columnName = "_id")
private long id;

ORMLite requires us to have column named id.

Uh, no. ORMLite shouldn't care what the name of your column is. Maybe you are talking about Android?

I am trying to write that query and return Cursor from this query.

Is this is a different question?

java.sql.SQLException: Could not compile this SELECT_RAW statement since the caller is expecting a SELECT statement. Check your QueryBuilder methods.

You are getting this because you are calling:

newsArticleDao.queryBuilder().selectRaw(...);

And then calling:

query.prepare();

To quote from the javadocs of selectRaw(...)

... This will turn the query into something only suitable for the Dao.queryRaw(String, String...) type of statement.

I think you want to assign the name of your column using columnName. Have you looked at the javadocs for @DatabaseField? Or maybe look up "column name" in the online manual?

来源：https://stackoverflow.com/questions/21096426/how-to-rename-columns-in-ormlite

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android

sql

ormlite