Android 中的数据库操作
1创建数据库
继承SQLiteOpenHelper(抽象类) 。实现一下两个方法
abstract void
onCreate(SQLiteDatabase db)
Called when the database is created for the first time.
abstract void
onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
Called when the database needs to be upgraded.
2 数据的操作。（增删改查）
synchronized SQLiteDatabase
getReadableDatabase()
Create and/or open a database.
synchronized SQLiteDatabase
getWritableDatabase()
Create and/or open a database that will be used forreading and writing.
获得可读或可写的数据库。
通过 SQLiteDatabase 类进行数据操作。
常用方法如下：
void
close()
Close the database.
int
delete(String table, String whereClause, String[] whereArgs)
Convenience method for deleting rows in the database.
void
execSQL(String sql)
Execute a single SQL statement that is NOT a SELECT orany other SQL statement that returns data.
void
execSQL(String sql, Object[] bindArgs)
Execute a single SQL statement that is NOT aSELECT/INSERT/UPDATE/DELETE.
long
insert(String table, String nullColumnHack, ContentValues values)
Convenience method for inserting a row into thedatabase.
long
insertOrThrow(String table, String nullColumnHack, ContentValues values)
Convenience method for inserting a row into thedatabase.
boolean
isOpen()
boolean
isReadOnly()
return whether the DB is opened as read only.
static SQLiteDatabase
openDatabase(String path, SQLiteDatabase.CursorFactory factory, int flags, DatabaseErrorHandler errorHandler)
Open the database according to the flags OPEN_READWRITE OPEN_READONLY CREATE_IF_NECESSARY and/or NO_LOCALIZED_COLLATORS.
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, DatabaseErrorHandler errorHandler)
Equivalent to openDatabase(path, factory,CREATE_IF_NECESSARY, errorHandler).
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(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
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
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 theresult set.
static int
releaseMemory()
Attempts to release memory that SQLite holds but doesnot 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.
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