android-database

来源： https://stackoverflow.com/questions/54667625/can-i-make-non-primary-key-field-as-autogenerated-value-in-room

问题 My table is structure is as follows: @Entity(tableName = "userFitnessDailyRecords") public class UserFitnessDailyRecords { @NonNull @PrimaryKey private Date forDay; private int stepCount; } The query I am writing for getting sum and average is as follows: @Dao public interface UserFitnessDailyRecordsDao { @Query("SELECT SUM(stepCount), AVG(stepCount) FROM userFitnessDailyRecords where forDay BETWEEN :startDay AND :endDay ORDER BY forDay ASC") UserFitnessDailyRecords

问题 I am getting below exception only in android 9, after reinstalling everything looks good, Exception: android.database.sqlite.SQLiteBlobTooBigException: Row too big to fit into CursorWindow requiredPos=0, totalRows=1... Code: Cursor cursor = database.query(......); if(cursor == null || cursor.getCount() < 0) { //Here is the error Log.d("Error", "count : null"); return ""; } Edited: java.lang.RuntimeException: An error occurred while executing doInBackground() at android.os.AsyncTask$3.done

问题 i have two activities each one of them have a listview the first one is connected to a data base and get its data from strings.xml i want to send a row to the other listview in the aother activity and make it do the same as if it was in the first list view i did that before but all the data was saved in the database directly (no strnigs.xml) here is my code please help me public class DB_Sqlite extends SQLiteOpenHelper { public static final String BDname = "data.db"; public static final int

问题 I have an @Entity which holds a variable(list of custom object) along with other fields for the table. I am able to insert, fetch and delete from this entity. But I am facing an issue in updating the entity: I want to update that particular field which holds a list of custom object in the table but while compilation it throws an error: error: Query method parameters should either be a type that can be converted into a database column or a List / Array that contains such type. You can consider

问题 I am using date converter class to convert my date object. However, I still encounter an error saying. error: Cannot figure out how to save this field into a database. You can consider adding a type converter for it. My Date Converter class public class DateConverter { @TypeConverter public static Date toDate(Long dateLong){ return dateLong == null ? null: new Date(dateLong); } @TypeConverter public static long fromDate(Date date){ return date == null ? null :date.getTime(); } } My Database

问题 I have an activity which has two edit text fields: one for the title and the other for the story. The entries made two text fields are saved in the database, also the database has a ROW_ID , TITLE_ID and STORY_ID . The entries are displayed in a list view . When an item is long clicked, I get the row id corresponding to that item. How should I get the TITLE_ID and STORY_ID from this? 回答1: Say, you have the corresponing row id of item which is long clicked in a variable rid . Then run the

问题 I am working on a Solution in Xamarin which contains at least 4 different Android Applications. My Goal is to create a shared content provider for all of these four apps so that I can have the Master data in one place (If an application updates that data, I can get that updated version in another app). In Visual Studio, I have create a PCL project where I have defined the Content provider (which I can reference in all applications and do the CRUD operations). My Content Provider is as follows

问题 I want to store a video in sqlite database. P.S. I do not want to store the path but the actual video contents. I have converted the video in byte array and stored byte array in sqlite database. Upon retrieval bytearray is being converted into File. But video is not playing. Please help. 回答1: I want to store a video in sqlite database. P.S. I do not want to store the path but the actual video contents. Unless the videos are very short and take up little space (say up to 200k each, perhaps 1

问题 I have a table in my database, when adding new record I am checking if the record exists using the id.If it does, I want to update the record and if it doesn't add a new record. But am getting the exception: 2006-2259/? E/SQLiteDatabase﹕ Error inserting id=080333 phone=080333 total_owed=15050.0 total_debts=0 name=Alison Jones android.database.sqlite.SQLiteConstraintException: column id is not unique (code 19) This is the method that checks if a record exists: public boolean checkIfExists