Mkdir Com.Example.Sqlte3test

Sqllite3 操作簡介

在操作DOS環境下操作過程範例

執行SQL指令範例

sqlite3 command

http://www.sqlite.org/lang.html

http://www.tutorialspoint.com/sqlite/sqlite_commands.htm

基本指令

從Windows 進入DOS指令: [cmd]

adb shell

cd /data/data/

mkdir com.example.sqlte3test

cd com.example.sqlte3test

mkdir databases

sqlite3 company.db

create table employee (_id integer primary key, name text not null, age integer, salary integer);

insert into employee values (1, "Lu",50,50000);

insert into employee values (2, "Lee",30,40000);

insert into employee values (3, "Shu",35,35000);

insert into employee values (4, "Hwang",42,45000);

create table employee (_id integer primary key, name varchar(20) not null, age integer(3), salary integer(6)); => OK

create table Depart (dpno varchar(6) not null primary key, name varchar(20) not null, age integer(3), salary integer(6)); => OK

SQLite - CREATE Database

The SQLitesqlite3command is used to create new SQLite database. You do not need to have any special privilege to create a database.

Syntax:

Basic syntax of sqlite3 command is as follows:

$sqlite3 DatabaseName.db

Always, database name should be unique within the RDBMS.

Example:

If you want to create new database <testDB.db>, then SQLITE3 statement would be as follows:

$sqlite3 testDB.db

SQLite version 3.7.15.2 2013-01-09 11:53:05

Enter ".help" for instructions

Enter SQL statements terminated with a ";"

sqlite

Above command will create a filetestDB.dbin the current directory. This file will be used as database by SQLite engine. If you have noticed while creating database, sqlite3 command will provide asqlite>prompt after creating database file successfully.

Once a database is created, you can check it in the list of databases using SQLite

.databases

sqlite>.databases

seq name file

------

0 main /home/sqlite/testDB.db

.tables

Use to list all tables under the opened databases.

.schema employee

List the field list.

.quit

You will use SQLite.quitcommand to come out of the sqlite prompt as follows:

sqlite.quit

$

.dump

You can use.dumpdot command to export complete database in a text file using SQLite command at command prompt as follows:

$sqlite3 testDB.db .dump testDB.sql

Above command will convert the entire contents oftestDB.dbdatabase into SQLite statements and dump it into ASCII text filetestDB.sql. You can do restoration from the generated testDB.sql in simple way as follows:

$sqlite3 testDB.db testDB.sql

At this moment your database is empty, so you can try above two procedures once you have few tables and data in your database. For now, let's proceed to next chapter.

SQLite - Data Type

SQLite data type is an attribute that specifies type of data of any object. Each column, variable and expression has related data type in SQLite.

You would use these data types while creating your tables. SQLite uses a more general dynamic type system. In SQLite, the datatype of a value is associated with the value itself, not with its container.

SQLite Storage Classes:

Each value stored in an SQLite database has one of the following storage classes:

Storage Class / Description
NULL / The value is a NULL value.
INTEGER / The value is a signed integer, stored in 1, 2, 3, 4, 6, or 8 bytes depending on the magnitude of the value.
REAL / The value is a floating point value, stored as an 8-byte IEEE floating point number.
TEXT / The value is a text string, stored using the database encoding (UTF-8, UTF-16BE or UTF-16LE)
BLOB / The value is a blob of data, stored exactly as it was input.

SQLite storage class is slightly more general than a datatype. The INTEGER storage class, for example, includes 6 different integer datatypes of different lengths.

SQLite Affinity Type:

SQLite supports the concept oftype affinityon columns. Any column can still store any type of data but the preferred storage class for a column is called itsaffinity. Each table column in an SQLite3 database is assigned one of the following type affinities:

Affinity / Description
TEXT / This column stores all data using storage classes NULL, TEXT or BLOB.
NUMERIC / This column may contain values using all five storage classes.
INTEGER / Behaves the same as a column with NUMERIC affinity with an exception in a CAST expression.
REAL / Behaves like a column with NUMERIC affinity except that it forces integer values into floating point representation
NONE / A column with affinity NONE does not prefer one storage class over another and no attempt is made to coerce data from one storage class into another.

SQLite Affinity and Type Names:

Following table lists down various data type names which can be used while creating SQLite3 tables and corresponding applied affinity also has been shown:

Data Type / Affinity
·  INT
·  INTEGER
·  TINYINT
·  SMALLINT
·  MEDIUMINT
·  BIGINT
·  UNSIGNED BIG INT
·  INT2
·  INT8 / INTEGER
·  CHARACTER(20)
·  VARCHAR(255)
·  VARYING CHARACTER(255)
·  NCHAR(55)
·  NATIVE CHARACTER(70)
·  NVARCHAR(100)
·  TEXT
·  CLOB / TEXT
·  BLOB
·  no datatype specified / NONE
·  REAL
·  DOUBLE
·  DOUBLE PRECISION
·  FLOAT / REAL
·  NUMERIC
·  DECIMAL(10,5)
·  BOOLEAN
·  DATE
·  DATETIME / NUMERIC

Boolean Datatype:

SQLite does not have a separate Boolean storage class. Instead, Boolean values are stored as integers 0 (false) and 1 (true).

Date and Time Datatype:

SQLite does not have a separate storage class for storing dates and/or times, but SQLite is capable of storing dates and times as TEXT, REAL or INTEGER values.

Storage Class / Date Formate
TEXT / A date in a format like "YYYY-MM-DD HH:MM:SS.SSS".
REAL / The number of days since noon in Greenwich on November 24, 4714 B.C.
INTEGER / The number of seconds since 1970-01-01 00:00:00 UTC.

You can chose to store dates and times in any of these formats and freely convert between formats using the built-in date and time functions.

Android SQLite database and content provider - Tutorial

http://www.vogella.com/tutorials/AndroidSQLite/article.html

rawQuery

Cursor c=db.rawQuery("SQL_query",null);

int id[]=new int[c.getCount];

int i=0;

if (c.getCount() 0)

{

c.moveToFirst();

do {

id[i]=c.getInt(c.getColumnIndex("field_name"));

i++;

} while (c.moveToNext());

c.close();

}

Cursor c = sampleDB.rawQuery("SELECT FirstName, Age FROM "+

SAMPLE_TABLE_NAME+

" where Age > 10 LIMIT 5",null);

if(c !=null) {

if (c.moveToFirst()) {

do{

String firstName = c.getString(c.getColumnIndex("FirstName"));

intage = c.getInt(c.getColumnIndex("Age"));

results.add(""+ firstName +",Age: "+ age);

}while(c.moveToNext());

}

}

Example

http://alvinalexander.com/java/jwarehouse/android/core/tests/coretests/src/android/database/DatabaseCursorTest.java.shtml

SQLiteOpenHelper常用方法

getReadableDatabase():建立或開啟唯讀資料庫

getWritableDatabase():建立或開啟可讀寫資料庫

getDatabaseName():取得資料庫名

close():關閉資料庫

範例:

宣告公用物件

SQLiteDatabase myDb;

DatabaseHelper hlp; // DatabaseHelper 類別

Cursor cursor;

建立或開啟資料庫

hlp=new DatabaseHelper(getApplicationContext(),"myappdb.db",null,1);

取得資料庫物件參考

myDb =this.getReadableDatabase();

取得游標物件參考

String str="select * from "+ tbl + ";";

Cursor c=myDb.rawQuery(str,null);

DatabaseHelper 類別

public class DatabaseHelper extends SQLiteOpenHelper {

static Context mContext;

private SQLiteDatabase myDb;

Cursor cursor;

File file;

//建構函式

/*

public DatabaseHelper(Context context, String name, CursorFactory factory,

int version) {

super(context, name, factory, version);

mContext=context;

}

*/

public DatabaseHelper(Context context, String name,CursorFactory factory,int version) {

/*

* next code failed

super(context, name, null, version);

//以上指令將資料庫建立在系統內部記憶體

super(context, context.getExternalFilesDir(null).getAbsolutePath() + "storage/sdcard1/com.example.myappdb/database/" +

name, null, version); //Fail

*/

super(context, context.getExternalFilesDir(null).getAbsolutePath() + "/" +

name, null, version);

mContext=context;

//以上指令將資料庫建立在手機SD card記憶體

super(context, storage/sdcard0/android/data/com.example.myappdb/files/" + "/" +

name, null, version); //fail

}

//此方法在建立資料庫時執行

@Override

public void onCreate(SQLiteDatabase db) {

try {

//執行建立資料表的SQL指令

//db.execSQL("drop database myappdb.db");

//db.execSQL("drop table if exists _tblDEF");

//mContext.deleteDatabase("myappdb.db");

myDb=db;

reCreateSys(db);

}

catch(Exception e)

{

Log.e("MainLogger.Run.Exception", "" + e);

//Toast.makeText(DatabaseHelper.this, e.getMessage(), Toast.LENGTH_LONG).show();

}

finally

{

// txtData.setText("Unknown!");

}

}

@Override

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

reCreateSys(db);

}

}

SQLiteDatabase常用方法

參考網站: http://blog.csdn.net/ccwwff/article/details/5834482

http://developer.android.com/reference/android/database/sqlite/SQLiteDatabase.html

beginTransaction():以Exclusive開始一個交易範圍

beginTransactionNonExclusive():以非Exclusive開始一個交易範圍

end Transaction():結束交易範圍

create():建立記憶體備分資料庫

openDatabase()/openOrCreateDatabase():開啟資料庫

insert():新增紀錄

query():查詢紀錄

replace():以新值取代或新增一筆紀錄

update():修改紀錄

delete():刪除紀錄

execSQL():執行SQL

deleteDatabase():刪除資料路

Cursor

http://siyuantw.blogspot.tw/2013/08/android-sqlite.html

close():關閉cursor

取欄值

getBlob(index)

getFloat(index)

getInt(index)

getString(index)

getType(index):取型態

範例:

public void getFldValue(String tbl,String fld,String[] ary)

{

myDb =this.getReadableDatabase();

String str="select "+fld+ " from "+ tbl + " order by " + fld +";";

Cursor c=myDb.rawQuery(str,null);

int i;

if (c != null ) {

if (c.moveToFirst()) {

i=0;

do {

switch(c.getType (0))

{

case 1: //1 Cursor.FIELD_TYPE_INTEGER

ary[i]=String.valueOf(c.getInt(0));

break;

case 2: //2 Cursor.FIELD_TYPE_FLOAT

ary[i]=String.valueOf(c.getFloat(0));

break;

case 3: //3 Cursor.FIELD_TYPE_STRING

ary[i]=c.getString(0);

break;

}

i++;

}while(c.moveToNext());

}

}

myDb.close();

return;

}

getColumnCount():取攔數

getCount():取筆數

getPosition():目前記錄位置

isAfterLast():已至末筆之後

isBeforeFirst()已至初筆之前

isFirst():第一筆

isLast():最末筆

isNull(index):空值

move(offset):移至後幾筆

moveToFirst():移至第一筆

moveToLast():移至末筆

moveToNext():移置次筆

moveToPrevious():移置前筆

moveToPosition(position) :移至指定筆

rawQuery():搜尋紀錄 http://www.cnblogs.com/zheng11/archive/2013/04/01/2994533.html

ContentValues

put():加入鍵值對

clear():清除鍵值對

常用SQL指令

Create Table [Table_Name] ([Field Definition],[]...,[Primary Key (Field_Name,])

Field Definition : Field_Name Data_Type [null|not null] [default]

Drop Table [Table_Name]

Alter Table [Table_Name] ([New Name]|[New Field])

不能修改舊欄名或定義

資料處理指令

查看紀錄

Select [*|欄位串列] From Table_Name [Where 查詢條件] [Order by [排序欄名]] [Group By [群阻攔名]] [Limit 筆數]

新增紀錄

Inser Into Table_Name (欄位串列) Values (資料串列)

刪除紀錄

Delete From Table_Name [Where 查詢條件]

修改紀錄

Update Table_Name Set [欄名 = 新值, [欄名 = 新值, ]] Where 搜尋鍵值條件