RoomDatabase

Kotlin |Java

public abstract class RoomDatabase
extends Object

java.lang.Object
↳	androidx.room.RoomDatabase

Base class for all Room databases. All classes that are annotated with Database must extend this class.

RoomDatabase provides direct access to the underlying database implementation but you should prefer using Dao classes.

See also:

Database

Summary

Nested classes
`class`	`RoomDatabase.Builder<T extends RoomDatabase>` Builder for RoomDatabase.
`class`	`RoomDatabase.Callback` Callback for `RoomDatabase`.
`enum`	`RoomDatabase.JournalMode` Journal modes for SQLite database.
`class`	`RoomDatabase.MigrationContainer` A container to hold migrations.

Fields
`protected List<RoomDatabase.Callback>`	`mCallbacks` This field is deprecated. Will be hidden in the next release.
`protected SupportSQLiteDatabase`	`mDatabase` This field is deprecated. Will be hidden in the next release.

Public constructors
`RoomDatabase()` Creates a RoomDatabase.

Public methods
`void`	`beginTransaction()` This method is deprecated. Use `runInTransaction(Runnable)`
`abstract void`	`clearAllTables()` Deletes all rows from all the tables that are registered to this database as `Database.entities()`.
`void`	`close()` Closes the database if it is already open.
`SupportSQLiteStatement`	`compileStatement(String sql)` Wrapper for `SupportSQLiteDatabase.compileStatement(String)`.
`void`	`endTransaction()` This method is deprecated. Use `runInTransaction(Runnable)`
`InvalidationTracker`	`getInvalidationTracker()` Returns the invalidation tracker for this database.
`SupportSQLiteOpenHelper`	`getOpenHelper()` Returns the SQLite open helper used by this database.
`Executor`	`getQueryExecutor()`
`Executor`	`getTransactionExecutor()`
`boolean`	`inTransaction()` Returns true if current thread is in a transaction.
`void`	`init(DatabaseConfiguration configuration)` Called by `Room` when it is initialized.
`boolean`	`isOpen()` Returns true if database connection is open and initialized.
`Cursor`	`query(String query, Object[] args)` Convenience method to query the database with arguments.
`Cursor`	`query(SupportSQLiteQuery query, CancellationSignal signal)` Wrapper for `SupportSQLiteDatabase.query(SupportSQLiteQuery)`.
`Cursor`	`query(SupportSQLiteQuery query)` Wrapper for `SupportSQLiteDatabase.query(SupportSQLiteQuery)`.
`<V> V`	`runInTransaction(Callable<V> body)` Executes the specified `Callable` in a database transaction.
`void`	`runInTransaction(Runnable body)` Executes the specified `Runnable` in a database transaction.
`void`	`setTransactionSuccessful()` This method is deprecated. Use `runInTransaction(Runnable)`

Protected methods
`abstract InvalidationTracker`	`createInvalidationTracker()` Called when the RoomDatabase is created.
`abstract SupportSQLiteOpenHelper`	`createOpenHelper(DatabaseConfiguration config)` Creates the open helper to access the database.
`void`	`internalInitInvalidationTracker(SupportSQLiteDatabase db)` Called by the generated code when database is open.

Inherited methods

From class


        
          java.lang.Object

`Object`	`clone()`
`boolean`	`equals(Object arg0)`
`void`	`finalize()`
`final Class<?>`	`getClass()`
`int`	`hashCode()`
`final void`	`notify()`
`final void`	`notifyAll()`
`String`	`toString()`
`final void`	`wait(long arg0, int arg1)`
`final void`	`wait(long arg0)`
`final void`	`wait()`

Fields

mCallbacks

protected List<RoomDatabase.Callback> mCallbacks

This field is deprecated.
Will be hidden in the next release.

mDatabase

protected SupportSQLiteDatabase mDatabase

This field is deprecated.
Will be hidden in the next release.

Set by the generated open helper.

Public constructors

RoomDatabase

public RoomDatabase ()

Creates a RoomDatabase.

You cannot create an instance of a database, instead, you should acquire it via Room.databaseBuilder(Context, Class, String) or Room.inMemoryDatabaseBuilder(Context, Class).

Public methods

beginTransaction

public void beginTransaction ()

This method is deprecated.
Use runInTransaction(Runnable)

Wrapper for SupportSQLiteDatabase.beginTransaction().

clearAllTables

public abstract void clearAllTables ()

Deletes all rows from all the tables that are registered to this database as Database.entities().

This does NOT reset the auto-increment value generated by PrimaryKey.autoGenerate().

After deleting the rows, Room will set a WAL checkpoint and run VACUUM. This means that the data is completely erased. The space will be reclaimed by the system if the amount surpasses the threshold of database file size.

See also:

Database File Format

close

public void close ()

Closes the database if it is already open.

compileStatement

public SupportSQLiteStatement compileStatement (String sql)

Wrapper for SupportSQLiteDatabase.compileStatement(String).

Parameters
`sql`	`String`: The query to compile.

Returns
`SupportSQLiteStatement`	The compiled query.

endTransaction

public void endTransaction ()

This method is deprecated.
Use runInTransaction(Runnable)

Wrapper for SupportSQLiteDatabase.endTransaction().

getInvalidationTracker

public InvalidationTracker getInvalidationTracker ()

Returns the invalidation tracker for this database.

You can use the invalidation tracker to get notified when certain tables in the database are modified.

Returns
`InvalidationTracker`	The invalidation tracker for the database.

getOpenHelper

public SupportSQLiteOpenHelper getOpenHelper ()

Returns the SQLite open helper used by this database.

Returns
`SupportSQLiteOpenHelper`	The SQLite open helper used by this database.

getQueryExecutor

public Executor getQueryExecutor ()

Returns
`Executor`	The Executor in use by this database for async queries.

getTransactionExecutor

public Executor getTransactionExecutor ()

Returns
`Executor`	The Executor in use by this database for async transactions.

inTransaction

public boolean inTransaction ()

Returns true if current thread is in a transaction.

Returns
`boolean`	True if there is an active transaction in current thread, false otherwise.

See also:

SupportSQLiteDatabase.inTransaction()

init

public void init (DatabaseConfiguration configuration)

Called by Room when it is initialized.

Parameters
`configuration`	`DatabaseConfiguration`: The database configuration.

isOpen

public boolean isOpen ()

Returns true if database connection is open and initialized.

Returns
`boolean`	true if the database connection is open, false otherwise.

query

public Cursor query (String query, 
                Object[] args)

Convenience method to query the database with arguments.

Parameters
`query`	`String`: The sql query
`args`	`Object`: The bind arguments for the placeholders in the query

Returns
`Cursor`	A Cursor obtained by running the given query in the Room database.

query

public Cursor query (SupportSQLiteQuery query, 
                CancellationSignal signal)

Wrapper for SupportSQLiteDatabase.query(SupportSQLiteQuery).

Parameters
`query`	`SupportSQLiteQuery`: The Query which includes the SQL and a bind callback for bind arguments.
`signal`	`CancellationSignal`: The cancellation signal to be attached to the query.

Returns
`Cursor`	Result of the query.

query

public Cursor query (SupportSQLiteQuery query)

Wrapper for SupportSQLiteDatabase.query(SupportSQLiteQuery).

Parameters
`query`	`SupportSQLiteQuery`: The Query which includes the SQL and a bind callback for bind arguments.

Returns
`Cursor`	Result of the query.

runInTransaction

public V runInTransaction (Callable<V> body)

Executes the specified Callable in a database transaction. The transaction will be marked as successful unless an exception is thrown in the Callable.

Room will only perform at most one transaction at a time.

Parameters
`body`	`Callable`: The piece of code to execute.

Returns
`V`	The value returned from the `Callable`.

runInTransaction

public void runInTransaction (Runnable body)

Executes the specified Runnable in a database transaction. The transaction will be marked as successful unless an exception is thrown in the Runnable.

Room will only perform at most one transaction at a time.

Parameters
`body`	`Runnable`: The piece of code to execute.

setTransactionSuccessful

public void setTransactionSuccessful ()

This method is deprecated.
Use runInTransaction(Runnable)

Wrapper for SupportSQLiteDatabase.setTransactionSuccessful().

Protected methods

createInvalidationTracker

protected abstract InvalidationTracker createInvalidationTracker ()

Called when the RoomDatabase is created.

This is already implemented by the generated code.

Returns
`InvalidationTracker`	Creates a new InvalidationTracker.

createOpenHelper

protected abstract SupportSQLiteOpenHelper createOpenHelper (DatabaseConfiguration config)

Creates the open helper to access the database. Generated class already implements this method. Note that this method is called when the RoomDatabase is initialized.

Parameters
`config`	`DatabaseConfiguration`: The configuration of the Room database.

Returns
`SupportSQLiteOpenHelper`	A new SupportSQLiteOpenHelper to be used while connecting to the database.

internalInitInvalidationTracker

protected void internalInitInvalidationTracker (SupportSQLiteDatabase db)

Called by the generated code when database is open.

You should never call this method manually.

Parameters
`db`	`SupportSQLiteDatabase`: The database instance.

RoomDatabase

Summary

Nested classes

Fields

Public constructors

Public methods

Protected methods

Inherited methods

Fields

mCallbacks

mDatabase

Public constructors

RoomDatabase

Public methods

beginTransaction

clearAllTables

close

compileStatement

endTransaction

getInvalidationTracker

getOpenHelper

getQueryExecutor

getTransactionExecutor

inTransaction

init

isOpen

query

query

query

runInTransaction

runInTransaction

setTransactionSuccessful

Protected methods

createInvalidationTracker

createOpenHelper

internalInitInvalidationTracker