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android - SQLite Android 从其他字段更新字段

转载 作者:行者123 更新时间:2023-11-30 03:45:14 24 4
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我正在尝试通过组合其他三个整数字段来更新我的 SQLite 数据库中的一个整数字段,但如果字段值的长度为 1,我还需要在其他字段中的两个前面加上一个零。

这是我尝试通过我的 DBAdapter 类中的升级数据库方法执行的例程。

所以我需要更改当前的更新:

if (newVersion==2) {
populatesql = "update " + DB_TABLE +
" set field1="+ COL_FIELD2 +
" || " +
COL_FIELD3 +
" || " +
COL_FIELD4;
}

类似这样的事情(是的,我知道 prefixzero 不起作用,因为它需要字符串而不是整数,但我尝试使用字符串并将其设为静态,但它不起作用)

if (newVersion==2) {
populatesql = "update " + DB_TABLE +
" set field1="+ COL_FIELD2 +
" || " +
prefixzero(COL_FIELD3) +
" || " +
prefixzero(COL_FIELD4);
}

public String prefixzero(String number) {
String result = Integer.toString(number);

// Log.d("PREFIX", "result starts with this = "+result);
if (result.length() >1 ) {
// Log.d("PREFIX", "NO ZEROES HERE");
return Integer.toString(number);
}

String zeroprefix = "";
zeroprefix = "0"+result;
// Log.d("PREFIX", zeroprefix);

return zeroprefix ;
}

数据库字段声明如下:

public static final String COL_FIELD4 = "day";
public static final String COL_FIELD3 = "month";
public static final String COL_FIELD2 = "year";
public static final String COL_FIELD1 = "long_date";

这是我遗漏空格的错误。就像没有空格一样,字段名称只是简单地连接在一起。使用的代码低于此错误。

02-28 07:34:00.919: E/AndroidRuntime(18332): java.lang.RuntimeException: Unable to start activity ComponentInfo{co.uk.common.myapp/co.uk.common.myapp.MainActivity}: android.database.sqlite.SQLiteException: no such column: yearmonthday: update Log set long_date= yearmonthday
02-28 07:34:00.919: E/AndroidRuntime(18332): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1658)
02-28 07:34:00.919: E/AndroidRuntime(18332): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1674)
02-28 07:34:00.919: E/AndroidRuntime(18332): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
02-28 07:34:00.919: E/AndroidRuntime(18332): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:942)
02-28 07:34:00.919: E/AndroidRuntime(18332): at android.os.Handler.dispatchMessage(Handler.java:99)
02-28 07:34:00.919: E/AndroidRuntime(18332): at android.os.Looper.loop(Looper.java:130)
02-28 07:34:00.919: E/AndroidRuntime(18332): at android.app.ActivityThread.main(ActivityThread.java:3735)
02-28 07:34:00.919: E/AndroidRuntime(18332): at java.lang.reflect.Method.invokeNative(Native Method)
02-28 07:34:00.919: E/AndroidRuntime(18332): at java.lang.reflect.Method.invoke(Method.java:507)
02-28 07:34:00.919: E/AndroidRuntime(18332): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
02-28 07:34:00.919: E/AndroidRuntime(18332): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:662)
02-28 07:34:00.919: E/AndroidRuntime(18332): at dalvik.system.NativeStart.main(Native Method)
02-28 07:34:00.919: E/AndroidRuntime(18332): Caused by: android.database.sqlite.SQLiteException: no such column: yearmonthday: update Log set long_date= yearmonthday
02-28 07:34:00.919: E/AndroidRuntime(18332): at android.database.sqlite.SQLiteDatabase.native_execSQL(Native Method)
02-28 07:34:00.919: E/AndroidRuntime(18332): at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:1763)
02-28 07:34:00.919: E/AndroidRuntime(18332): at co.uk.shieldstothemax.blastedneighbours.DBAdapter$DBHelper.onUpgrade(DBAdapter.java:68)
02-28 07:34:00.919: E/AndroidRuntime(18332): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:132)
02-28 07:34:00.919: E/AndroidRuntime(18332): at co.uk.shieldstothemax.blastedneighbours.DBAdapter.open(DBAdapter.java:87)
02-28 07:34:00.919: E/AndroidRuntime(18332): at co.uk.shieldstothemax.blastedneighbours.MainActivity.onCreate(MainActivity.java:123)
02-28 07:34:00.919: E/AndroidRuntime(18332): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-28 07:34:00.919: E/AndroidRuntime(18332): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1622)

onUpgrade 方法中的代码:

if (newVersion==2) {

populatesql = "update "+ DB_TABLE +" set long_date= "+getDateStr(COL_FIELD2,COL_FIELD3,COL_FIELD4);
}

getDateStr:

public static String getDateStr(String year, String month,String day) {
return year+ prefixfieldzero(month)+ prefixfieldzero(day);
}

前缀字段零:

public static String prefixfieldzero(String number) {
String result = String.valueOf(number);
// Log.d("PREFIX", "result starts with this = "+result);
if (result.length() >1 ) {
// Log.d("PREFIX", "NO ZEROES HERE");
return number;
}

String zerofieldprefix = "";
zerofieldprefix = "0"+result;
// Log.d("PREFIX", zeroprefix);

return zerofieldprefix ;
}

这是我的 DBAdapter:

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;


public class DBAdapter {
private static final String DB_NAME = "TABLE";
private static final String DB_TABLE = "Log";
private static final int DB_VERSION = 2;

private static final String DB_CREATE = "CREATE TABLE IF NOT EXISTS "+DB_TABLE+
" (_id INTEGER PRIMARY KEY AUTOINCREMENT, " +
"type_id INTEGER, " +" hour INTEGER, " +
"min INTEGER , " +" info VARCHAR,"+"image_desc VARCHAR, "+
"day INTEGER, "+"month INTEGER, "+ "year INTEGER,"+" second INTEGER,long_date INTEGER ,date_time_long INTEGER NOT NULL "+");" ;


public static final String COL_TYPE = "type_id";
public static final String COL_HOUR = "hour";
public static final String COL_MIN = "min";
public static final String COL_SEC = "second";
public static final String COL_IMAGE = "image_desc";

public static final String COL_DAY = "day";
public static final String COL_MON = "month";
public static final String COL_YEAR = "year";
public static final String COL_DATE = "date";
public static final String COL_LONG_DATE = "long_date";
public static final String COL_INFO = "info";
public static final String COL_ID = "_id";

private SQLiteDatabase mDB;
private DBHelper mDBHelper;
private Context mCtx;

private static class DBHelper extends SQLiteOpenHelper{
public DBHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(DB_CREATE);

}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.v("OLDDBVERSION", "Old version="+String.valueOf(oldVersion));
Log.v("NEWDBVERSION", "New version="+String.valueOf(newVersion));
//String upgradesql = null;
String populatesql = null;
if (newVersion==2) {

populatesql = "update "+ DB_TABLE +" set long_date= "+getDateStr(COL_YEAR,COL_MON,COL_DAY);
}
if (populatesql !=null) {
//db.execSQL(upgradesql);
if (populatesql !=null) {

db.execSQL(populatesql);
}
}



}
}

public DBAdapter(Context ctx)
{
this.mCtx = ctx;
}

//OPEN METHOD AND CLOSE METHOD
public DBAdapter open()
{
mDBHelper = new DBHelper(mCtx);
mDB = mDBHelper.getWritableDatabase(); //important
return this;
}

public void close()
{
mDBHelper.close();
}

//INSERT AND DELETE
public long createLog(String info,String image, Integer type,Integer hour,Integer mins,Integer sec,Integer day,Integer month,Integer year,Long longdate,Long date)
{
ContentValues v = new ContentValues();
v.put(COL_TYPE, type);
v.put(COL_INFO, info);
v.put(COL_IMAGE, image);
v.put(COL_HOUR, hour);
v.put(COL_SEC, sec);
v.put(COL_MIN, mins);
v.put(COL_DAY, day);
v.put(COL_MON, month);
v.put(COL_YEAR, year);
v.put(COL_DATE, date);
v.put(COL_LONG_DATE, longdate);

return mDB.insert(DB_TABLE, null, v);
}

public boolean deleteLogRec(long id)
{
return mDB.delete(DB_TABLE, COL_ID + "="+ id, null)>0;
}

public boolean deleteAllLogs()
{
return mDB.delete(DB_TABLE, null, null)>0;
}

//get all bookmark
public Cursor GetAllLogs(Integer i,String sortfield)
{
String sorted = "";
if (i == 1 ) {
sorted = "DESC";
} else if (i == 2) {
sorted = "ASC";
}


return mDB.query(DB_TABLE, new String[] {COL_ID, COL_TYPE,COL_IMAGE, COL_INFO,COL_IMAGE,COL_HOUR,COL_SEC,COL_MIN,COL_DAY,COL_MON,COL_YEAR,COL_SORT_DATE},
null, null, null, null, COL_DATE+" "+sorted);
}

public Cursor allrecords() {

return mDB.query(DB_TABLE, new String[] {COL_ID, COL_TYPE,COL_IMAGE, COL_INFO,COL_IMAGE,COL_HOUR,COL_SEC,COL_MIN,COL_DAY,COL_MON,COL_YEAR,COL_SORT_DATE},
null, null, null, null, null);
}





//get a specific log by id
public Cursor getLog(long id)
{
Cursor mCursor = mDB.query(true, DB_TABLE, new String[] {COL_ID, COL_TYPE,COL_IMAGE, COL_INFO,COL_IMAGE,COL_HOUR,COL_SEC,COL_MIN,COL_DAY,COL_MON,COL_YEAR},
COL_ID + "=" + id,
null, null, null, null, null);

if (mCursor!=null)
mCursor.moveToFirst();
return mCursor;
}

//finally update the log
public boolean updateLog(long id, String uinfo, String uimage,Integer utype,Integer uhour,Integer usec,Integer umin,Integer uday,Integer umonth,Integer uyear,Long ulongdate,Long udate)
{
ContentValues v = new ContentValues();
v.put(COL_TYPE, utype);
v.put(COL_INFO, uinfo);
v.put(COL_IMAGE, uimage);
v.put(COL_HOUR, uhour);
v.put(COL_SEC, usec);
v.put(COL_MIN, umin);
v.put(COL_DAY, uday);
v.put(COL_MON, umonth);
v.put(COL_YEAR, uyear);
v.put(COL_DATE, udate);
v.put(COL_SORT_DATE, ulongdate);

return mDB.update(DB_TABLE, v, COL_ID + "=" + id, null) > 0;
}

public static String prefixfieldzero(String number) {
String result = String.valueOf(number);
// Log.d("PREFIX", "result starts with this = "+result);
if (result.length() >1 ) {
// Log.d("PREFIX", "NO ZEROES HERE");
return number;
}

String zerofieldprefix = "";
zerofieldprefix = "0"+result;
// Log.d("PREFIX", zeroprefix);

return zerofieldprefix ;
}

public static String getDateStr(String year, String month,String day) {
return year+ prefixfieldzero(month)+ prefixfieldzero(day);
}


}

尝试根据您的最新答案运行 SQL,但出现此错误:

03-01 00:20:05.379: E/AndroidRuntime(19060): Caused by: android.database.sqlite.SQLiteException: near "AS": syntax error: update TABLE AS TABLE_Temp1 set long_date = (select year || substr('00' || month ,-2,2  ) || substr('00' || ,day, -2 ,2)  from Log AS TABLE_Temp2 where TABLE_Temp1.id=TABLE_Temp2.id   

当前用于将长日期更新为年月日组合的 SQL:

populatesql = "update "+DB_TABLE + " AS LogTemp1 set long_date = (select year || substr('00' || month ,-2,2  ) || substr('00' || ,day, -2 ,2)  from "+DB_TABLE+" AS LogTemp2 where LogTemp1.id=LogTemp2.id   "  ; 

我也试过如下:

populatesql = "update "+DB_TABLE + " AS LogTemp1 set long_date = (select year || substr('00' || month ,-2,2  ) || substr('00' || ,day, -2 ,2)  from "+DB_TABLE+" AS LogTemp2 where **LogTemp1._id=LogTemp2._id**   "  ; 

最佳答案

好吧,我终于得到了,你想要的。您需要一个更新语句来根据其当前值更新每一行。当然,您不能从 SQLite 数据库调用 Java 代码中的函数。因此,一切都必须在 SQLite 本身的 UPDATE 语句中完成。

鉴于此,您的陈述应如下所示:

UPDATE yourTable AS table1 
SET date =
(SELECT year ||
substr('00' || month, -2, 2) ||
substr('00' || day, -2, 2)
FROM yourTable AS table2
WHERE table1.id = table2.id);

您只需将我在这里使用的名称替换为您实际使用的名称,并生成一个有效的 Java 字符串。

substr('00' || month, -2, 2) 语句执行其他数据库引擎的 lpad 语句(在 SQLite 中不可用)会做。

您可以这样读:将两个零与一个数字连接起来,然后取结果字符串最右边的两个字符。 -2表示子串从右边开始计数,2表示取两个字符作为结果子串。

lpad 替换基于 a blogpost通过 Jason Hinkle .

关于android - SQLite Android 从其他字段更新字段,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/15118370/

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