SupportSQLiteDatabase

beginTransaction

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();
   }
 

beginTransactionNonExclusive

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();
   }
 

beginTransactionWithListener

void beginTransactionWithListener (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();
   }
 

beginTransactionWithListenerNonExclusive

void beginTransactionWithListenerNonExclusive (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();
   }
 

compileStatement

SupportSQLiteStatement compileStatement (String sql)

Compiles the given SQL statement.

delete

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

Convenience method for deleting rows in the database.

disableWriteAheadLogging

void disableWriteAheadLogging ()

This method disables the features enabled by enableWriteAheadLogging().

enableWriteAheadLogging

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(SQLiteTransactionListener) 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 ENABLE_WRITE_AHEAD_LOGGING flag to openDatabase(File, SQLiteDatabase.OpenParams). 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.

endTransaction

void endTransaction ()

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

execSQL

void execSQL (String sql, 
                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()

execSQL

void execSQL (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()

getAttachedDbs

List<Pair<String, String>> getAttachedDbs ()

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

getMaximumSize

long getMaximumSize ()

Returns the maximum size the database may grow to.

getPageSize

long getPageSize ()

Returns the current database page size, in bytes.

getPath

String getPath ()

Gets the path to the database file.

getVersion

int getVersion ()

Gets the database version.

inTransaction

boolean inTransaction ()

Returns true if the current thread has a transaction pending.

insert

long insert (String table, 
                int conflictAlgorithm, 
                ContentValues values)

Convenience method for inserting a row into the database.

isDatabaseIntegrityOk

boolean isDatabaseIntegrityOk ()

Runs 'pragma integrity_check' on the given database (and all the attached databases) and returns true if the given database (and all its attached databases) pass integrity_check, false otherwise.

If the result is false, then this method logs the errors reported by the integrity_check command execution.

Note that 'pragma integrity_check' on a database can take a long time.

isDbLockedByCurrentThread

boolean isDbLockedByCurrentThread ()

Returns 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.

isOpen

boolean isOpen ()

Returns true if the database is currently open.

isReadOnly

boolean isReadOnly ()

Returns true if the database is opened as read only.

isWriteAheadLoggingEnabled

boolean isWriteAheadLoggingEnabled ()

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

needUpgrade

boolean needUpgrade (int newVersion)

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

query

Cursor query (SupportSQLiteQuery query)

Runs the given query on the database.

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

query

Cursor query (String query)

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

query

Cursor query (String query, 
                Object[] bindArgs)

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

query

Cursor query (SupportSQLiteQuery query, 
                CancellationSignal cancellationSignal)

Runs the given query on the database.

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

setForeignKeyConstraintsEnabled

void setForeignKeyConstraintsEnabled (boolean enable)

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 onConfigure(SupportSQLiteDatabase) 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.

setLocale

void setLocale (Locale locale)

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

setMaxSqlCacheSize

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.

setMaximumSize

long setMaximumSize (long numBytes)

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

setPageSize

void setPageSize (long numBytes)

Sets the database page size. 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.

setTransactionSuccessful

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.

setVersion

void setVersion (int version)

Sets the database version.

update

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

Convenience method for updating rows in the database.

yieldIfContendedSafely

boolean yieldIfContendedSafely (long sleepAfterYieldDelay)

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.

yieldIfContendedSafely

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.