Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>I have come to conclusion (working on my app JReader which relies on fast DB operations a lot) that SQLite in Android is pretty quick as in other platforms but there are some Android specific issues. Some advises regarding database performance and the questions you have asked:</p> <ul> <li>Content providers are mostly useless if you are not planning sharing your data through them. But they provide at least 2 advantages. First you get data change notifications and you cursor gets updated automatically, and the second and important one: CursorLoaders require a Content provider, and if the performance matters to you, I would strongly suggest using them for loading your cursor;</li> <li>Accessing Collections is much faster that accessing database, but it is a double work, since you have to persist the data anyway, and DB access is quite fast even for fetching data for a super-fast scrolling list and especially from a single table, it shouldn't be a problem;</li> <li>Design your DB properly (with JOINS, indexes, etc) :) BUT DO NOT USE JOIN QUERIES IN CURSOR QUERIES! I have had lots of performance issues with that on multiple Android platforms (including 4.0+), not always though. The way I access joint tables is by simply getting foreign key first and then querying child table.</li> </ul> <p>In my experience, I've had the situations when the DB performance was very poor, but in the end I have always managed to tweak the code and as a result would gain 10-100 fold performance increase. So keep profiling you DB code, and you will definitely achieve the desired performance.</p>
    singulars
    1. This table or related slice is empty.
    1. POAndroid: Extending user's contact book. Performance ContentProvider vs Sqlite vs List in memory
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USRahim
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POAndroid: Extending user's contact book. Performance ContentProvider vs Sqlite vs List in memory
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COAnd I totally agree with Dan's 1st comment, but not the 2nd one
      singulars
      1. PO
      1. USRahim
    2. COYour third bullet is exactly what my question is about. How can you design your DB properly (with joins indexes etc) without using joins in the cursor queries? You mean by not using a CursorAdapter and query the DB with a join at start up and keep the result in a List in memory?
      singulars
      1. PO
      1. USjelgh
    3. CO"The way I access joint tables is by simply getting foreign key first and then querying child table." What do you mean by that? First querying table A with some foreign key X and then querying table B for each X? So that you do size of X + 1 number of queries? Or how do you mean?
      singulars
      1. PO
      1. USjelgh
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload