SupportSQLiteDatabase

abstract void beginTransaction()

Begins a transaction in EXCLUSIVE mode.

Transactions can be nested. When the outer transaction is ended all of the work done in that transaction and all of the nested transactions will be committed or rolled back. The changes will be rolled back if any transaction is ended without being marked as clean (by calling setTransactionSuccessful). Otherwise they will be committed.

Here is the standard idiom for transactions:

db.beginTransaction()
try {
    ...
    db.setTransactionSuccessful()
} finally {
    db.endTransaction()
}

abstract void beginTransactionNonExclusive()

Begins a transaction in IMMEDIATE mode. Transactions can be nested. When the outer transaction is ended all of the work done in that transaction and all of the nested transactions will be committed or rolled back. The changes will be rolled back if any transaction is ended without being marked as clean (by calling setTransactionSuccessful). Otherwise they will be committed.

Here is the standard idiom for transactions:

db.beginTransactionNonExclusive()
try {
    ...
    db.setTransactionSuccessful()
} finally {
    db.endTransaction()
}

default void beginTransactionReadOnly()

Begins a transaction in DEFERRED mode, with the android-specific constraint that the transaction is read-only. The database may not be modified inside a read-only transaction otherwise a android.database.sqlite.SQLiteDatabaseLockedException might be thrown.

Read-only transactions may run concurrently with other read-only transactions, and if they database is in WAL mode, they may also run concurrently with IMMEDIATE or EXCLUSIVE transactions.

Transactions can be nested. However, the behavior of the transaction is not altered by nested transactions. A nested transaction may be any of the three transaction types but if the outermost type is read-only then nested transactions remain read-only, regardless of how they are started.

Here is the standard idiom for read-only transactions:

db.beginTransactionReadOnly();
try {
  ...
} finally {
  db.endTransaction();
}

If the implementation does not support read-only transactions then the default implementation delegates to beginTransaction.

abstract void beginTransactionWithListener(
    @NonNull SQLiteTransactionListener transactionListener
)

Begins a transaction in EXCLUSIVE mode.

Transactions can be nested. When the outer transaction is ended all of the work done in that transaction and all of the nested transactions will be committed or rolled back. The changes will be rolled back if any transaction is ended without being marked as clean (by calling setTransactionSuccessful). Otherwise they will be committed.

Here is the standard idiom for transactions:

db.beginTransactionWithListener(listener)
try {
    ...
    db.setTransactionSuccessful()
} finally {
    db.endTransaction()
}

abstract void beginTransactionWithListenerNonExclusive(
    @NonNull SQLiteTransactionListener transactionListener
)

Begins a transaction in IMMEDIATE mode. Transactions can be nested. When the outer transaction is ended all of the work done in that transaction and all of the nested transactions will be committed or rolled back. The changes will be rolled back if any transaction is ended without being marked as clean (by calling setTransactionSuccessful). Otherwise they will be committed.

Here is the standard idiom for transactions:

db.beginTransactionWithListenerNonExclusive(listener)
try {
    ...
    db.setTransactionSuccessful()
} finally {
    db.endTransaction()
}

default void beginTransactionWithListenerReadOnly(
    @NonNull SQLiteTransactionListener transactionListener
)

Begins a transaction in read-only mode with a {@link SQLiteTransactionListener} listener. The database may not be modified inside a read-only transaction otherwise a android.database.sqlite.SQLiteDatabaseLockedException might be thrown.

Transactions can be nested. However, the behavior of the transaction is not altered by nested transactions. A nested transaction may be any of the three transaction types but if the outermost type is read-only then nested transactions remain read-only, regardless of how they are started.

Here is the standard idiom for read-only transactions:

db.beginTransactionWightListenerReadOnly(listener);
try {
  ...
} finally {
  db.endTransaction();
}

If the implementation does not support read-only transactions then the default implementation delegates to beginTransactionWithListener.

abstract @NonNull SupportSQLiteStatement compileStatement(@NonNull String sql)

Compiles the given SQL statement.

abstract int delete(@NonNull String table, String whereClause, Object[] whereArgs)

Convenience method for deleting rows in the database.

abstract void disableWriteAheadLogging()

This method disables the features enabled by enableWriteAheadLogging.

abstract boolean enableWriteAheadLogging()

This method enables parallel execution of queries from multiple threads on the same database. It does this by opening multiple connections to the database and using a different database connection for each query. The database journal mode is also changed to enable writes to proceed concurrently with reads.

When write-ahead logging is not enabled (the default), it is not possible for reads and writes to occur on the database at the same time. Before modifying the database, the writer implicitly acquires an exclusive lock on the database which prevents readers from accessing the database until the write is completed.

In contrast, when write-ahead logging is enabled (by calling this method), write operations occur in a separate log file which allows reads to proceed concurrently. While a write is in progress, readers on other threads will perceive the state of the database as it was before the write began. When the write completes, readers on other threads will then perceive the new state of the database.

It is a good idea to enable write-ahead logging whenever a database will be concurrently accessed and modified by multiple threads at the same time. However, write-ahead logging uses significantly more memory than ordinary journaling because there are multiple connections to the same database. So if a database will only be used by a single thread, or if optimizing concurrency is not very important, then write-ahead logging should be disabled.

After calling this method, execution of queries in parallel is enabled as long as the database remains open. To disable execution of queries in parallel, either call disableWriteAheadLogging or close the database and reopen it.

The maximum number of connections used to execute queries in parallel is dependent upon the device memory and possibly other properties.

If a query is part of a transaction, then it is executed on the same database handle the transaction was begun.

Writers should use beginTransactionNonExclusive or beginTransactionWithListenerNonExclusive to start a transaction. Non-exclusive mode allows database file to be in readable by other threads executing queries.

If the database has any attached databases, then execution of queries in parallel is NOT possible. Likewise, write-ahead logging is not supported for read-only databases or memory databases. In such cases, enableWriteAheadLogging returns false.

The best way to enable write-ahead logging is to pass the android.database.sqlite.SQLiteDatabase.ENABLE_WRITE_AHEAD_LOGGING flag to android.database.sqlite.SQLiteDatabase.openDatabase. This is more efficient than calling

SQLiteDatabase db = SQLiteDatabase.openDatabase("db_filename", cursorFactory, SQLiteDatabase.CREATE_IF_NECESSARY | SQLiteDatabase.ENABLE_WRITE_AHEAD_LOGGING, myDatabaseErrorHandler) db.enableWriteAheadLogging()

Another way to enable write-ahead logging is to call enableWriteAheadLogging after opening the database.

SQLiteDatabase db = SQLiteDatabase.openDatabase("db_filename", cursorFactory, SQLiteDatabase.CREATE_IF_NECESSARY, myDatabaseErrorHandler) db.enableWriteAheadLogging()

See also SQLite Write-Ahead Logging for more details about how write-ahead logging works.

abstract void endTransaction()

End a transaction. See beginTransaction for notes about how to use this and when transactions are committed and rolled back.

default void execPerConnectionSQL(@NonNull String sql, Object[] bindArgs)

Execute the given SQL statement on all connections to this database.

This statement will be immediately executed on all existing connections, and will be automatically executed on all future connections.

Some example usages are changes like PRAGMA trusted_schema=OFF or functions like SELECT icu_load_collation(). If you execute these statements using execSQL then they will only apply to a single database connection; using this method will ensure that they are uniformly applied to all current and future connections.

An implementation of SupportSQLiteDatabase might not support this operation. Use isExecPerConnectionSQLSupported to check if this operation is supported before calling this method.

abstract void execSQL(@NonNull String sql)

Execute a single SQL statement that does not return any data.

When using enableWriteAheadLogging, journal_mode is automatically managed by this class. So, do not set journal_mode using "PRAGMA journal_mode" statement if your app is using enableWriteAheadLogging

abstract void execSQL(@NonNull String sql, @NonNull Object[] bindArgs)

Execute a single SQL statement that does not return any data.

When using enableWriteAheadLogging, journal_mode is automatically managed by this class. So, do not set journal_mode using "PRAGMA journal_mode" statement if your app is using enableWriteAheadLogging

abstract List<@NonNull Pair<@NonNull String, @NonNull String>> getAttachedDbs()

The list of full path names of all attached databases including the main database by executing 'pragma database_list' on the database.

abstract long getMaximumSize()

The maximum size the database may grow to.

abstract long getPageSize()

The current database page size, in bytes.

The page size must be a power of two. This method does not work if any data has been written to the database file, and must be called right after the database has been created.

abstract String getPath()

The path to the database file.

abstract int getVersion()

The database version.

abstract boolean inTransaction()

Returns true if the current thread has a transaction pending.

abstract long insert(
    @NonNull String table,
    int conflictAlgorithm,
    @NonNull ContentValues values
)

Convenience method for inserting a row into the database.

abstract boolean isDatabaseIntegrityOk()

Is true if the given database (and all its attached databases) pass integrity_check, false otherwise.

abstract boolean isDbLockedByCurrentThread()

True if the current thread is holding an active connection to the database.

The name of this method comes from a time when having an active connection to the database meant that the thread was holding an actual lock on the database. Nowadays, there is no longer a true "database lock" although threads may block if they cannot acquire a database connection to perform a particular operation.

default boolean isExecPerConnectionSQLSupported()

Is true if execPerConnectionSQL is supported by the implementation.

abstract boolean isOpen()

Is true if the database is currently open.

abstract boolean isReadOnly()

Is true if the database is opened as read only.

abstract boolean isWriteAheadLoggingEnabled()

Is true if write-ahead logging has been enabled for this database.

abstract boolean needUpgrade(int newVersion)

Returns true if the new version code is greater than the current database version.

abstract @NonNull Cursor query(@NonNull String query)

Runs the given query on the database. If you would like to have typed bind arguments, use query.

abstract @NonNull Cursor query(@NonNull SupportSQLiteQuery query)

Runs the given query on the database.

This class allows using type safe sql program bindings while running queries.

abstract @NonNull Cursor query(@NonNull String query, @NonNull Object[] bindArgs)

Runs the given query on the database. If you would like to have bind arguments, use query.

abstract @NonNull Cursor query(
    @NonNull SupportSQLiteQuery query,
    CancellationSignal cancellationSignal
)

Runs the given query on the database.

This class allows using type safe sql program bindings while running queries.

abstract void setForeignKeyConstraintsEnabled(boolean enabled)

Sets whether foreign key constraints are enabled for the database.

By default, foreign key constraints are not enforced by the database. This method allows an application to enable foreign key constraints. It must be called each time the database is opened to ensure that foreign key constraints are enabled for the session.

A good time to call this method is right after calling #openOrCreateDatabase or in the SupportSQLiteOpenHelper.Callback.onConfigure callback.

When foreign key constraints are disabled, the database does not check whether changes to the database will violate foreign key constraints. Likewise, when foreign key constraints are disabled, the database will not execute cascade delete or update triggers. As a result, it is possible for the database state to become inconsistent. To perform a database integrity check, call isDatabaseIntegrityOk.

This method must not be called while a transaction is in progress.

See also SQLite Foreign Key Constraints for more details about foreign key constraint support.

abstract void setLocale(@NonNull Locale locale)

Sets the locale for this database. Does nothing if this database has the android.database.sqlite.SQLiteDatabase.NO_LOCALIZED_COLLATORS flag set or was opened read only.

abstract void setMaxSqlCacheSize(int cacheSize)

Sets the maximum size of the prepared-statement cache for this database. (size of the cache = number of compiled-sql-statements stored in the cache).

Maximum cache size can ONLY be increased from its current size (default = 10). If this method is called with smaller size than the current maximum value, then IllegalStateException is thrown.

This method is thread-safe.

abstract long setMaximumSize(long numBytes)

Sets the maximum size the database will grow to. The maximum size cannot be set below the current size.

abstract void setPageSize(long pageSize)

The current database page size, in bytes.

The page size must be a power of two. This method does not work if any data has been written to the database file, and must be called right after the database has been created.

abstract void setTransactionSuccessful()

Marks the current transaction as successful. Do not do any more database work between calling this and calling endTransaction. Do as little non-database work as possible in that situation too. If any errors are encountered between this and endTransaction the transaction will still be committed.

abstract void setVersion(int version)

The database version.

abstract int update(
    @NonNull String table,
    int conflictAlgorithm,
    @NonNull ContentValues values,
    String whereClause,
    Object[] whereArgs
)

Convenience method for updating rows in the database.

abstract boolean yieldIfContendedSafely()

Temporarily end the transaction to let other threads run. The transaction is assumed to be successful so far. Do not call setTransactionSuccessful before calling this. When this returns a new transaction will have been created but not marked as successful. This assumes that there are no nested transactions (beginTransaction has only been called once) and will throw an exception if that is not the case.

abstract boolean yieldIfContendedSafely(long sleepAfterYieldDelayMillis)

Temporarily end the transaction to let other threads run. The transaction is assumed to be successful so far. Do not call setTransactionSuccessful before calling this. When this returns a new transaction will have been created but not marked as successful. This assumes that there are no nested transactions (beginTransaction has only been called once) and will throw an exception if that is not the case.