public class

SQLiteDatabase

extends SQLiteClosable
java.lang.Object
   ↳ android.database.sqlite.SQLiteClosable
     ↳ android.database.sqlite.SQLiteDatabase

Class Overview

Exposes methods to manage a SQLite database.

SQLiteDatabase has methods to create, delete, execute SQL commands, and perform other common database management tasks.

See the Notepad sample application in the SDK for an example of creating and managing a database.

Database names must be unique within an application, not across all applications.

Localized Collation - ORDER BY

In addition to SQLite's default BINARY collator, Android supplies two more, LOCALIZED, which changes with the system's current locale if you wire it up correctly (XXX a link needed!), and UNICODE, which is the Unicode Collation Algorithm and not tailored to the current locale.

Summary

Nested Classes
public class SQLiteDatabase.CursorFactory Used to allow returning sub-classes of Cursor when calling query. 
Constants
int CREATE_IF_NECESSARY Flag for openDatabase(String, SQLiteDatabase.CursorFactory, int) to create the database file if it does not already exist.
int NO_LOCALIZED_COLLATORS Flag for openDatabase(String, SQLiteDatabase.CursorFactory, int) to open the database without support for localized collators.
int OPEN_READONLY Flag for openDatabase(String, SQLiteDatabase.CursorFactory, int) to open the database for reading only.
int OPEN_READWRITE Flag for openDatabase(String, SQLiteDatabase.CursorFactory, int) to open the database for reading and writing. If the disk is full, this may fail even before you actually write anything.
int SQLITE_MAX_LIKE_PATTERN_LENGTH Maximum Length Of A LIKE Or GLOB Pattern The pattern matching algorithm used in the default LIKE and GLOB implementation of SQLite can exhibit O(N^2) performance (where N is the number of characters in the pattern) for certain pathological cases.
Public Methods
void beginTransaction()
Begins a transaction.
void close()
Close the database.
SQLiteStatement compileStatement(String sql)
Compiles an SQL statement into a reusable pre-compiled statement object.
static SQLiteDatabase create(SQLiteDatabase.CursorFactory factory)
Create a memory backed SQLite database.
int delete(String table, String whereClause, String[] whereArgs)
Convenience method for deleting rows in the database.
void endTransaction()
End a transaction.
void execSQL(String sql, Object[] bindArgs)
Execute a single SQL statement that is not a query.
void execSQL(String sql)
Execute a single SQL statement that is not a query.
static String findEditTable(String tables)
Finds the name of the first table, which is editable.
long getMaximumSize()
Returns the maximum size the database may grow to.
long getPageSize()
Returns the current database page size, in bytes.
final String getPath()
Getter for the path to the database file.
Map<StringString> getSyncedTables()
int getVersion()
Gets the database version.
boolean inTransaction()
return true if there is a transaction pending
long insert(String table, String nullColumnHack, ContentValues values)
Convenience method for inserting a row into the database.
long insertOrThrow(String table, String nullColumnHack, ContentValues values)
Convenience method for inserting a row into the database.
boolean isDbLockedByCurrentThread()
Checks if the database lock is held by this thread.
boolean isDbLockedByOtherThreads()
Checks if the database is locked by another thread.
boolean isOpen()
boolean isReadOnly()
return whether the DB is opened as read only.
void markTableSyncable(String table, String deletedTable)
Mark this table as syncable.
void markTableSyncable(String table, String foreignKey, String updateTable)
Mark this table as syncable, with the _sync_dirty residing in another table.
boolean needUpgrade(int newVersion)
static SQLiteDatabase openDatabase(String path, SQLiteDatabase.CursorFactory factory, int flags)
Open the database according to the flags OPEN_READWRITE OPEN_READONLY CREATE_IF_NECESSARY and/or NO_LOCALIZED_COLLATORS.
static SQLiteDatabase openOrCreateDatabase(String path, SQLiteDatabase.CursorFactory factory)
Equivalent to openDatabase(path, factory, CREATE_IF_NECESSARY).
static SQLiteDatabase openOrCreateDatabase(File file, SQLiteDatabase.CursorFactory factory)
Equivalent to openDatabase(file.getPath(), factory, CREATE_IF_NECESSARY).
Cursor query(String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy, String limit)
Query the given table, returning a Cursor over the result set.
Cursor query(boolean distinct, String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy, String limit)
Query the given URL, returning a Cursor over the result set.
Cursor query(String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy)
Query the given table, returning a Cursor over the result set.
Cursor queryWithFactory(SQLiteDatabase.CursorFactory cursorFactory, boolean distinct, String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy, String limit)
Query the given URL, returning a Cursor over the result set.
Cursor rawQuery(String sql, String[] selectionArgs)
Runs the provided SQL and returns a Cursor over the result set.
Cursor rawQueryWithFactory(SQLiteDatabase.CursorFactory cursorFactory, String sql, String[] selectionArgs, String editTable)
Runs the provided SQL and returns a cursor over the result set.
static int releaseMemory()
Attempts to release memory that SQLite holds but does not require to operate properly.
long replace(String table, String nullColumnHack, ContentValues initialValues)
Convenience method for replacing a row in the database.
long replaceOrThrow(String table, String nullColumnHack, ContentValues initialValues)
Convenience method for replacing a row in the database.
void setLocale(Locale locale)
Sets the locale for this database.
void setLockingEnabled(boolean lockingEnabled)
Control whether or not the SQLiteDatabase is made thread-safe by using locks around critical sections.
long setMaximumSize(long numBytes)
Sets the maximum size the database will grow to.
void setPageSize(long numBytes)
Sets the database page size.
void setTransactionSuccessful()
Marks the current transaction as successful.
void setVersion(int version)
Sets the database version.
int update(String table, ContentValues values, String whereClause, String[] whereArgs)
Convenience method for updating rows in the database.
boolean yieldIfContended()
This method is deprecated. if the db is locked more than once (becuase of nested transactions) then the lock will not be yielded. Use yieldIfContendedSafely instead.
boolean yieldIfContendedSafely()
Temporarily end the transaction to let other threads run.
Protected Methods
void finalize()
Is called before the object's memory is being reclaimed by the VM.
void onAllReferencesReleased()
[Expand]
Inherited Methods
From class android.database.sqlite.SQLiteClosable
From class java.lang.Object

Constants

public static final int CREATE_IF_NECESSARY

Flag for openDatabase(String, SQLiteDatabase.CursorFactory, int) to create the database file if it does not already exist.

Constant Value: 268435456 (0x10000000)

public static final int NO_LOCALIZED_COLLATORS

Flag for openDatabase(String, SQLiteDatabase.CursorFactory, int) to open the database without support for localized collators.

This causes the collator LOCALIZED not to be created. You must be consistent when using this flag to use the setting the database was created with. If this is set, setLocale(Locale) will do nothing.

Constant Value: 16 (0x00000010)

public static final int OPEN_READONLY

Flag for openDatabase(String, SQLiteDatabase.CursorFactory, int) to open the database for reading only. This is the only reliable way to open a database if the disk may be full.

Constant Value: 1 (0x00000001)

public static final int OPEN_READWRITE

Flag for openDatabase(String, SQLiteDatabase.CursorFactory, int) to open the database for reading and writing. If the disk is full, this may fail even before you actually write anything.

Note that the value of this flag is 0, so it is the default.

Constant Value: 0 (0x00000000)

public static final int SQLITE_MAX_LIKE_PATTERN_LENGTH

Maximum Length Of A LIKE Or GLOB Pattern The pattern matching algorithm used in the default LIKE and GLOB implementation of SQLite can exhibit O(N^2) performance (where N is the number of characters in the pattern) for certain pathological cases. To avoid denial-of-service attacks the length of the LIKE or GLOB pattern is limited to SQLITE_MAX_LIKE_PATTERN_LENGTH bytes. The default value of this limit is 50000. A modern workstation can evaluate even a pathological LIKE or GLOB pattern of 50000 bytes relatively quickly. The denial of service problem only comes into play when the pattern length gets into millions of bytes. Nevertheless, since most useful LIKE or GLOB patterns are at most a few dozen bytes in length, paranoid application developers may want to reduce this parameter to something in the range of a few hundred if they know that external users are able to generate arbitrary patterns.

Constant Value: 50000 (0x0000c350)

Public Methods

public void beginTransaction ()

Begins a transaction. 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();
   }
 

public void close ()

Close the database.

public SQLiteStatement compileStatement (String sql)

Compiles an SQL statement into a reusable pre-compiled statement object. The parameters are identical to execSQL(String). You may put ?s in the statement and fill in those values with bindString(int, String) and bindLong(int, long) each time you want to run the statement. Statements may not return result sets larger than 1x1.

Parameters
sql The raw SQL statement, may contain ? for unknown values to be bound later.
Returns
  • a pre-compiled statement object.
Throws
SQLException

public static SQLiteDatabase create (SQLiteDatabase.CursorFactory factory)

Create a memory backed SQLite database. Its contents will be destroyed when the database is closed.

Sets the locale of the database to the the system's current locale. Call setLocale(Locale) if you would like something else.

Parameters
factory an optional factory class that is called to instantiate a cursor when query is called
Returns
  • a SQLiteDatabase object, or null if the database can't be created

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

Convenience method for deleting rows in the database.

Parameters
table the table to delete from
whereClause the optional WHERE clause to apply when deleting. Passing null will delete all rows.
Returns
  • the number of rows affected if a whereClause is passed in, 0 otherwise. To remove all rows and get a count pass "1" as the whereClause.

public void endTransaction ()

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

public void execSQL (String sql, Object[] bindArgs)

Execute a single SQL statement that is not a query. For example, CREATE TABLE, DELETE, INSERT, etc. Multiple statements separated by ;s are not supported. it takes a write lock,

Parameters
bindArgs only byte[], String, Long and Double are supported in bindArgs.
Throws
SQLException If the SQL string is invalid for some reason

public void execSQL (String sql)

Execute a single SQL statement that is not a query. For example, CREATE TABLE, DELETE, INSERT, etc. Multiple statements separated by ;s are not supported. it takes a write lock

Throws
SQLException If the SQL string is invalid for some reason

public static String findEditTable (String tables)

Finds the name of the first table, which is editable.

Parameters
tables a list of tables
Returns
  • the first table listed

public long getMaximumSize ()

Returns the maximum size the database may grow to.

Returns
  • the new maximum database size

public long getPageSize ()

Returns the current database page size, in bytes.

Returns
  • the database page size, in bytes

public final String getPath ()

Getter for the path to the database file.

Returns
  • the path to our database file.

public Map<StringString> getSyncedTables ()

public int getVersion ()

Gets the database version.

Returns
  • the database version

public boolean inTransaction ()

return true if there is a transaction pending

public long insert (String table, String nullColumnHack, ContentValues values)

Convenience method for inserting a row into the database.

Parameters
table the table to insert the row into
nullColumnHack SQL doesn't allow inserting a completely empty row, so if initialValues is empty this column will explicitly be assigned a NULL value
values this map contains the initial column values for the row. The keys should be the column names and the values the column values
Returns
  • the row ID of the newly inserted row, or -1 if an error occurred

public long insertOrThrow (String table, String nullColumnHack, ContentValues values)

Convenience method for inserting a row into the database.

Parameters
table the table to insert the row into
nullColumnHack SQL doesn't allow inserting a completely empty row, so if initialValues is empty this column will explicitly be assigned a NULL value
values this map contains the initial column values for the row. The keys should be the column names and the values the column values
Returns
  • the row ID of the newly inserted row, or -1 if an error occurred
Throws
SQLException
SQLException

public boolean isDbLockedByCurrentThread ()

Checks if the database lock is held by this thread.

Returns
  • true, if this thread is holding the database lock.

public boolean isDbLockedByOtherThreads ()

Checks if the database is locked by another thread. This is just an estimate, since this status can change at any time, including after the call is made but before the result has been acted upon.

Returns
  • true, if the database is locked by another thread

public boolean isOpen ()

Returns
  • true if the DB is currently open (has not been closed)

public boolean isReadOnly ()

return whether the DB is opened as read only.

Returns
  • true if DB is opened as read only

public void markTableSyncable (String table, String deletedTable)

Mark this table as syncable. When an update occurs in this table the _sync_dirty field will be set to ensure proper syncing operation.

Parameters
table the table to mark as syncable
deletedTable The deleted table that corresponds to the syncable table

public void markTableSyncable (String table, String foreignKey, String updateTable)

Mark this table as syncable, with the _sync_dirty residing in another table. When an update occurs in this table the _sync_dirty field of the row in updateTable with the _id in foreignKey will be set to ensure proper syncing operation.

Parameters
table an update on this table will trigger a sync time removal
foreignKey this is the column in table whose value is an _id in updateTable
updateTable this is the table that will have its _sync_dirty

public boolean needUpgrade (int newVersion)

public static SQLiteDatabase openDatabase (String path, SQLiteDatabase.CursorFactory factory, int flags)

Open the database according to the flags OPEN_READWRITE OPEN_READONLY CREATE_IF_NECESSARY and/or NO_LOCALIZED_COLLATORS.

Sets the locale of the database to the the system's current locale. Call setLocale(Locale) if you would like something else.

Parameters
path to database file to open and/or create
factory an optional factory class that is called to instantiate a cursor when query is called, or null for default
flags to control database access mode
Returns
  • the newly opened database
Throws
SQLiteException if the database cannot be opened

public static SQLiteDatabase openOrCreateDatabase (String path, SQLiteDatabase.CursorFactory factory)

Equivalent to openDatabase(path, factory, CREATE_IF_NECESSARY).

public static SQLiteDatabase openOrCreateDatabase (File file, SQLiteDatabase.CursorFactory factory)

Equivalent to openDatabase(file.getPath(), factory, CREATE_IF_NECESSARY).

public Cursor query (String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy, String limit)

Query the given table, returning a Cursor over the result set.

Parameters
table The table name to compile the query against.
columns A list of which columns to return. Passing null will return all columns, which is discouraged to prevent reading data from storage that isn't going to be used.
selection A filter declaring which rows to return, formatted as an SQL WHERE clause (excluding the WHERE itself). Passing null will return all rows for the given table.
selectionArgs You may include ?s in selection, which will be replaced by the values from selectionArgs, in order that they appear in the selection. The values will be bound as Strings.
groupBy A filter declaring how to group rows, formatted as an SQL GROUP BY clause (excluding the GROUP BY itself). Passing null will cause the rows to not be grouped.
having A filter declare which row groups to include in the cursor, if row grouping is being used, formatted as an SQL HAVING clause (excluding the HAVING itself). Passing null will cause all row groups to be included, and is required when row grouping is not being used.
orderBy How to order the rows, formatted as an SQL ORDER BY clause (excluding the ORDER BY itself). Passing null will use the default sort order, which may be unordered.
limit Limits the number of rows returned by the query, formatted as LIMIT clause. Passing null denotes no LIMIT clause.
Returns
  • A Cursor object, which is positioned before the first entry
See Also

public Cursor query (boolean distinct, String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy, String limit)

Query the given URL, returning a Cursor over the result set.

Parameters
distinct true if you want each row to be unique, false otherwise.
table The table name to compile the query against.
columns A list of which columns to return. Passing null will return all columns, which is discouraged to prevent reading data from storage that isn't going to be used.
selection A filter declaring which rows to return, formatted as an SQL WHERE clause (excluding the WHERE itself). Passing null will return all rows for the given table.
selectionArgs You may include ?s in selection, which will be replaced by the values from selectionArgs, in order that they appear in the selection. The values will be bound as Strings.
groupBy A filter declaring how to group rows, formatted as an SQL GROUP BY clause (excluding the GROUP BY itself). Passing null will cause the rows to not be grouped.
having A filter declare which row groups to include in the cursor, if row grouping is being used, formatted as an SQL HAVING clause (excluding the HAVING itself). Passing null will cause all row groups to be included, and is required when row grouping is not being used.
orderBy How to order the rows, formatted as an SQL ORDER BY clause (excluding the ORDER BY itself). Passing null will use the default sort order, which may be unordered.
limit Limits the number of rows returned by the query, formatted as LIMIT clause. Passing null denotes no LIMIT clause.
Returns
  • A Cursor object, which is positioned before the first entry
See Also

public Cursor query (String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy)

Query the given table, returning a Cursor over the result set.

Parameters
table The table name to compile the query against.
columns A list of which columns to return. Passing null will return all columns, which is discouraged to prevent reading data from storage that isn't going to be used.
selection A filter declaring which rows to return, formatted as an SQL WHERE clause (excluding the WHERE itself). Passing null will return all rows for the given table.
selectionArgs You may include ?s in selection, which will be replaced by the values from selectionArgs, in order that they appear in the selection. The values will be bound as Strings.
groupBy A filter declaring how to group rows, formatted as an SQL GROUP BY clause (excluding the GROUP BY itself). Passing null will cause the rows to not be grouped.
having A filter declare which row groups to include in the cursor, if row grouping is being used, formatted as an SQL HAVING clause (excluding the HAVING itself). Passing null will cause all row groups to be included, and is required when row grouping is not being used.
orderBy How to order the rows, formatted as an SQL ORDER BY clause (excluding the ORDER BY itself). Passing null will use the default sort order, which may be unordered.
Returns
  • A Cursor object, which is positioned before the first entry
See Also

public Cursor queryWithFactory (SQLiteDatabase.CursorFactory cursorFactory, boolean distinct, String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy, String limit)

Query the given URL, returning a Cursor over the result set.

Parameters
cursorFactory the cursor factory to use, or null for the default factory
distinct true if you want each row to be unique, false otherwise.
table The table name to compile the query against.
columns A list of which columns to return. Passing null will return all columns, which is discouraged to prevent reading data from storage that isn't going to be used.
selection A filter declaring which rows to return, formatted as an SQL WHERE clause (excluding the WHERE itself). Passing null will return all rows for the given table.
selectionArgs You may include ?s in selection, which will be replaced by the values from selectionArgs, in order that they appear in the selection. The values will be bound as Strings.
groupBy A filter declaring how to group rows, formatted as an SQL GROUP BY clause (excluding the GROUP BY itself). Passing null will cause the rows to not be grouped.
having A filter declare which row groups to include in the cursor, if row grouping is being used, formatted as an SQL HAVING clause (excluding the HAVING itself). Passing null will cause all row groups to be included, and is required when row grouping is not being used.
orderBy How to order the rows, formatted as an SQL ORDER BY clause (excluding the ORDER BY itself). Passing null will use the default sort order, which may be unordered.
limit Limits the number of rows returned by the query, formatted as LIMIT clause. Passing null denotes no LIMIT clause.
Returns
  • A Cursor object, which is positioned before the first entry
See Also

public Cursor rawQuery (String sql, String[] selectionArgs)

Runs the provided SQL and returns a Cursor over the result set.

Parameters
sql the SQL query. The SQL string must not be ; terminated
selectionArgs You may include ?s in where clause in the query, which will be replaced by the values from selectionArgs. The values will be bound as Strings.
Returns
  • A Cursor object, which is positioned before the first entry

public Cursor rawQueryWithFactory (SQLiteDatabase.CursorFactory cursorFactory, String sql, String[] selectionArgs, String editTable)

Runs the provided SQL and returns a cursor over the result set.

Parameters
cursorFactory the cursor factory to use, or null for the default factory
sql the SQL query. The SQL string must not be ; terminated
selectionArgs You may include ?s in where clause in the query, which will be replaced by the values from selectionArgs. The values will be bound as Strings.
editTable the name of the first table, which is editable
Returns
  • A Cursor object, which is positioned before the first entry

public static int releaseMemory ()

Attempts to release memory that SQLite holds but does not require to operate properly. Typically this memory will come from the page cache.

Returns
  • the number of bytes actually released

public long replace (String table, String nullColumnHack, ContentValues initialValues)

Convenience method for replacing a row in the database.

Parameters
table the table in which to replace the row
nullColumnHack SQL doesn't allow inserting a completely empty row, so if initialValues is empty this row will explicitly be assigned a NULL value
initialValues this map contains the initial column values for the row. The key
Returns
  • the row ID of the newly inserted row, or -1 if an error occurred

public long replaceOrThrow (String table, String nullColumnHack, ContentValues initialValues)

Convenience method for replacing a row in the database.

Parameters
table the table in which to replace the row
nullColumnHack SQL doesn't allow inserting a completely empty row, so if initialValues is empty this row will explicitly be assigned a NULL value
initialValues this map contains the initial column values for the row. The key
Returns
  • the row ID of the newly inserted row, or -1 if an error occurred
Throws
SQLException
SQLException

public 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.

Throws
SQLException if the locale could not be set. The most common reason for this is that there is no collator available for the locale you requested. In this case the database remains unchanged.

public void setLockingEnabled (boolean lockingEnabled)

Control whether or not the SQLiteDatabase is made thread-safe by using locks around critical sections. This is pretty expensive, so if you know that your DB will only be used by a single thread then you should set this to false. The default is true.

Parameters
lockingEnabled set to true to enable locks, false otherwise

public long setMaximumSize (long numBytes)

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

Parameters
numBytes the maximum database size, in bytes
Returns
  • the new maximum database size

public 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.

Parameters
numBytes the database page size, in bytes

public 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.

Throws
IllegalStateException if the current thread is not in a transaction or the transaction is already marked as successful.

public void setVersion (int version)

Sets the database version.

Parameters
version the new database version

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

Convenience method for updating rows in the database.

Parameters
table the table to update in
values a map from column names to new column values. null is a valid value that will be translated to NULL.
whereClause the optional WHERE clause to apply when updating. Passing null will update all rows.
Returns
  • the number of rows affected

public boolean yieldIfContended ()

This method is deprecated.if the db is locked more than once (becuase of nested transactions) then the lock will not be yielded. Use yieldIfContendedSafely instead.

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.

Returns
  • true if the transaction was yielded

public 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 through an exception if that is not the case.

Returns
  • true if the transaction was yielded

Protected Methods

protected void finalize ()

Is called before the object's memory is being reclaimed by the VM. This can only happen once the VM has detected, during a run of the garbage collector, that the object is no longer reachable by any thread of the running application.

The method can be used to free system resources or perform other cleanup before the object is garbage collected. The default implementation of the method is empty, which is also expected by the VM, but subclasses can override finalize() as required. Uncaught exceptions which are thrown during the execution of this method cause it to terminate immediately but are otherwise ignored.

Note that the VM does guarantee that finalize() is called at most once for any object, but it doesn't guarantee when (if at all) finalize() will be called. For example, object B's finalize() can delay the execution of object A's finalize() method and therefore it can delay the reclamation of A's memory. To be safe, use a ReferenceQueue, because it provides more control over the way the VM deals with references during garbage collection.

protected void onAllReferencesReleased ()