I would like to check whether a record exists or not.
Here is what I've tried:
MainActivity.class
public void onTextChanged(CharSequence s, int start, int before, int count) {
System.out.println("Ontext changed " + new String(s.toString()));
strDocumentFrom = s.toString();
if(s.toString().isEmpty()){
} else {
try{
strTransactionDate = dbHelper.getTransactionDateByDocumentNumber(strDocumentFrom);
//strTotalAmount = dbHelper.getTotalAmountByDocumentNumber(strDocumentFrom);
//strVan = dbHelper.getVanByDocumentNumber(strDocumentFrom);
//etTransactionDate.setText(strTransactionDate);
//etTotalAmount.setText(strTotalAmount);
//Log.d("Van", "" + strVan);
//etVan.setText(strVan);
} catch (SQLiteException e) {
e.printStackTrace();
Toast.makeText(ReceivingStocksHeader.this,
"Document number does not exist.", Toast.LENGTH_SHORT).show();
}
}
DBHelper.class
// TODO DISPLAYING RECORDS TO TRANSRCVHEADER
public String getTransactionDateByDocumentNumber(String strDocumentNumber){
String[] columns = new String[]{KEY_TRANSACTIONDATE};
Cursor c = myDataBase.query(TBL_INTRANS,
columns, null,
null, null, null, null, null);
if(c != null){
c.moveToFirst();
String date = c.getString(0);
return date;
} else {
Log.d("Error", "No record exists");
}
return null;
}
But it doesn't get it to the catch block to display the toast.
What am I doing wrong in here?
public static boolean CheckIsDataAlreadyInDBorNot(String TableName,
String dbfield, String fieldValue) {
SQLiteDatabase sqldb = EGLifeStyleApplication.sqLiteDatabase;
String Query = "Select * from " + TableName + " where " + dbfield + " = " + fieldValue;
Cursor cursor = sqldb.rawQuery(Query, null);
if(cursor.getCount() <= 0){
cursor.close();
return false;
}
cursor.close();
return true;
}
I hope this is useful to you...
This function returns true if record already exists in db. Otherwise returns false.
These are all good answers, however many forget to close the cursor and database. If you don't close the cursor or database you may run in to memory leaks.
Additionally: You can get an error when searching by String that contains non alpha/numeric characters. For example: "1a5f9ea3-ec4b-406b-a567-e6927640db40". Those dashes (-) will cause an unrecognized token error. You can overcome this by putting the string in an array. So make it a habit to query like this:
public boolean hasObject(String id) {
SQLiteDatabase db = getWritableDatabase();
String selectString = "SELECT * FROM " + _TABLE + " WHERE " + _ID + " =?";
// Add the String you are searching by here.
// Put it in an array to avoid an unrecognized token error
Cursor cursor = db.rawQuery(selectString, new String[] {id});
boolean hasObject = false;
if(cursor.moveToFirst()){
hasObject = true;
//region if you had multiple records to check for, use this region.
int count = 0;
while(cursor.moveToNext()){
count++;
}
//here, count is records found
Log.d(TAG, String.format("%d records found", count));
//endregion
}
cursor.close(); // Dont forget to close your cursor
db.close(); //AND your Database!
return hasObject;
}
Raw queries are more vulnerable to SQL Injection. I will suggest using query() method instead.
public boolean Exists(String searchItem) {
String[] columns = { COLUMN_NAME };
String selection = COLUMN_NAME + " =?";
String[] selectionArgs = { searchItem };
String limit = "1";
Cursor cursor = db.query(TABLE_NAME, columns, selection, selectionArgs, null, null, null, limit);
boolean exists = (cursor.getCount() > 0);
cursor.close();
return exists;
}
Source: here
SELECT EXISTS with LIMIT 1 is much faster.
Query Ex: SELECT EXISTS (SELECT * FROM table_name WHERE column='value' LIMIT 1);
Code Ex:
public boolean columnExists(String value) {
String sql = "SELECT EXISTS (SELECT * FROM table_name WHERE column='"+value+"' LIMIT 1)";
Cursor cursor = database.rawQuery(sql, null);
cursor.moveToFirst();
// cursor.getInt(0) is 1 if column with value exists
if (cursor.getInt(0) == 1) {
cursor.close();
return true;
} else {
cursor.close();
return false;
}
}
You can use SELECT EXISTS command and execute it for a cursor using a rawQuery,
from the documentation
The EXISTS operator always evaluates to one of the integer values 0
and 1. If executing the SELECT statement specified as the right-hand
operand of the EXISTS operator would return one or more rows, then the
EXISTS operator evaluates to 1. If executing the SELECT would return
no rows at all, then the EXISTS operator evaluates to 0.
I have tried all methods mentioned in this page, but only below method worked well for me.
Cursor c=db.rawQuery("SELECT * FROM user WHERE idno='"+txtID.getText()+"'", null);
if(c.moveToFirst())
{
showMessage("Error", "Record exist");
}
else
{
// Inserting record
}
One thing the top voted answer did not mention was that you need single quotes, 'like this', around your search value if it is a text value like so:
public boolean checkIfMyTitleExists(String title) {
String Query = "Select * from " + TABLE_NAME + " where " + COL1 + " = " + "'" + title + "'";
Cursor cursor = database.rawQuery(Query, null);
if(cursor.getCount() <= 0){
cursor.close();
return false;
}
cursor.close();
return true;
}
Otherwise, you will get a "SQL(query) error or missing database" error like I did without the single quotes around the title field.
If it is a numeric value, it does not need single quotes.
Refer to this SQL post for more details
SQLiteDatabase sqldb = MyProvider.db;
String Query = "Select * from " + TABLE_NAME ;
Cursor cursor = sqldb.rawQuery(Query, null);
cursor.moveToLast(); //if you not place this cursor.getCount() always give same integer (1) or current position of cursor.
if(cursor.getCount()<=0){
Log.v("tag","if 1 "+cursor.getCount());
return false;
}
Log.v("tag","2 else "+cursor.getCount());
return true;
if you not use cursor.moveToLast();
cursor.getCount() always give same integer (1) or current position of cursor.
Code :
private String[] allPushColumns = { MySQLiteHelper.COLUMN_PUSH_ID,
MySQLiteHelper.COLUMN_PUSH_TITLE, MySQLiteHelper.COLUMN_PUSH_CONTENT, MySQLiteHelper.COLUMN_PUSH_TIME,
MySQLiteHelper.COLUMN_PUSH_TYPE, MySQLiteHelper.COLUMN_PUSH_MSG_ID};
public boolean checkUniqueId(String msg_id){
Cursor cursor = database.query(MySQLiteHelper.TABLE_PUSH,
allPushColumns, MySQLiteHelper.COLUMN_PUSH_MSG_ID + "=?", new String [] { msg_id }, null, null, MySQLiteHelper.COLUMN_PUSH_ID +" DESC");
if(cursor.getCount() <= 0){
return false;
}
return true;
}
Here's a simple solution based on a combination of what dipali and Piyush Gupta posted:
public boolean dbHasData(String searchTable, String searchColumn, String searchKey) {
String query = "Select * from " + searchTable + " where " + searchColumn + " = ?";
return getReadableDatabase().rawQuery(query, new String[]{searchKey}).moveToFirst();
}
because of possible data leaks best solution via cursor:
Cursor cursor = null;
try {
cursor = .... some query (raw or not your choice)
return cursor.moveToNext();
} finally {
if (cursor != null) {
cursor.close();
}
}
1) From API KITKAT u can use resources try()
try (cursor = ...some query)
2) if u query against VARCHAR TYPE use '...' eg. COLUMN_NAME='string_to_search'
3) dont use moveToFirst() is used when you need to start iterating from beggining
4) avoid getCount() is expensive - it iterates over many records to count them. It doesn't return a stored variable. There may be some caching on a second call, but the first call doesn't know the answer until it is counted.
Try to use cursor.isNull method.
Example:
song.isFavorite = cursor.isNull(cursor.getColumnIndex("favorite"));
You can use like this:
String Query = "Select * from " + TABLE_NAME + " where " + Cust_id + " = " + cust_no;
Cursor cursorr = db.rawQuery(Query, null);
if(cursor.getCount() <= 0){
cursorr.close();
}
cursor.close();
private boolean checkDataExistOrNot(String columnName, String value) {
SQLiteDatabase sqLiteDatabase = getReadableDatabase();
String query = "SELECT * FROM" + TABLE_NAME + " WHERE " + columnName + " = " + value;
Cursor cursor = sqLiteDatabase.rawQuery(query, null);
if (cursor.getCount() <= 0) {
cursor.close();
return false; // return false if value not exists in database
}
cursor.close();
return true; // return true if value exists in database
}
I prefer to do it this way because it's fast and less expensive than other methods:
Cursor cursor = db.rawQuery("SELECT 1 FROM table WHERE condition = 1 LIMIT 1", null);
try {
if (cursor.moveToNext()) {
//Record exists
} else {
//Record doesn't exists
}
} finally {
cursor.close();
}
My version:
public boolean isTitleExists(String title, String type) {
int isExists = 0;
try {
String query = "SELECT EXISTS (SELECT 1 FROM titles WHERE title = ? and type = ?)";
PreparedStatement statement = connection.prepareStatement(query);
statement.setString(1, title);
statement.setString(2, type);
ResultSet rs = statement.executeQuery();
rs.next();
isExists = rs.getInt(1);
rs.close();
statement.close();
} catch (SQLException e) {
Common.console("isTitleExists error: " + e.getMessage());
}
return isExists == 1;
}
Related
I am using the following method to query my SQLite database with LIKE statement.
public List<Bean> getWords(String englishWord) {
if(englishWord.equals(""))
return new ArrayList<Bean>();
String sql = "SELECT * FROM " + TABLE_NAME +
" WHERE " + ENGLISH + " LIKE ? ORDER BY LENGTH(" + ENGLISH + ") LIMIT 100";
SQLiteDatabase db = initializer.getReadableDatabase();
Cursor cursor = null;
try {
cursor = db.rawQuery(sql, new String[]{"%" + englishWord.trim() + "%"});
List<Bean> wordList = new ArrayList<Bean>();
while(cursor.moveToNext()) {
String english = cursor.getString(1);
String mal = cursor.getString(2);
wordList.add(new Bean(english, bangla));
}
return wordList;
} catch (SQLiteException exception) {
exception.printStackTrace();
return null;
} finally {
if (cursor != null)
cursor.close();
}
}
I would like to change the above code for that it will query for exact match. I tried to modify the code as below but I do not how to get the mal string.
public void getoneWords(String englishWord) {
String sql = "SELECT * FROM " + TABLE_NAME +
" WHERE " + ENGLISH + " =?";
SQLiteDatabase db = initializer.getReadableDatabase();
Cursor cursor = null;
try {
cursor = db.rawQuery(sql, new String[]{englishWord});
while(cursor.moveToNext()) {
String english = cursor.getString(1);
String mal = cursor.getString(2);
}
} finally {
if (cursor != null)
cursor.close();
}
}
Method getoneWords for what. You should return mal and english in this function.
return new Bean(english, mal);
If you need first word, just cursor.moveToFirst and delete while loop:
String english = cursor.getString(1);
String mal = cursor.getString(2);
return new Bean(english, mal);
I finally solved this problem myself.
public String getoneWords(String englishWord) {
String sql = "SELECT * FROM " + TABLE_NAME +
" WHERE " + ENGLISH + " =?";
SQLiteDatabase db = initializer.getReadableDatabase();
Cursor cursor = null;
String meaning = "";
try {
cursor = db.rawQuery(sql, new String[] {englishWord});
if(cursor.getCount() > 0) {
cursor.moveToFirst();
meaning = cursor.getString(2);
}
return meaning;
}finally {
cursor.close();
}
}
In your getoneWords() you are not returning the queried values.
As you have two return values you would either need to wrap them in a Pair or create a "holder" Object (e.g. class Words(String english, String mal)) for the return values.
If your Query returns multiple matches you would need to return a list of those Objects. Otherwise, your above Code would just return the last match.
So you need to alter your function to return the queried
public Pair<String,String> getoneWords(String englishWord) {
Pair<String,String> result = null;
...
if(cursor.moveToNext()) {
String english = cursor.getString(1);
String mal = cursor.getString(2);
result = new Pair<String,String>(english, mal);
}
...
return result;
}
i have an issue with both functions
// Insert a new contact in database
public void insertInSignature(String TITLE_SI) {
try {
// Open Android Database
Boolean b = checkIsDataAlreadyInDBorNot("DELIVERY_SLIP",
"TITLE_SI", TITLE_SI);
if(b==false)
{
// cursor is empty
ContentValues initialValues = new ContentValues();
initialValues.put("TITLE_SI", TITLE_SI);
db.insertWithOnConflict("DELIVERY_SLIP", null, initialValues,
SQLiteDatabase.CONFLICT_IGNORE);
}
} catch (SQLException sqle) {
Log.e(TAG, "insertUser Error");
Log.e(TAG, "Exception : " + sqle);
} finally {
// Close Android Database
databaseHelper.close();
}
}
public boolean checkIsDataAlreadyInDBorNot(String TableName,
String dbfield, String fieldValue) {
db = databaseHelper.getWritableDatabase();
String Query = "Select * from " + TableName + " where " + dbfield + "="
+ "`"+ fieldValue+"`";
Cursor cursor = db.rawQuery(Query, null);
if (cursor.getCount() <= 0) {
return false;
}
return true;
}
I have this function , I'm inserting signature when it's not on the database.. But the function boolean return an SQLexception i don't know why i found informations about the form , but not for my problem.
Here my log.
http://hpics.li/0ae4ba2
I just want to know if the row exist on my database
here my table.
http://hpics.li/1fd3d9a
Thanks by advance if you need for informations ask me
In SQL, strings are delimited with single quotes ', not backticks `.
To avoid such formatting problems, and SQL injections, you should use parameters instead:
String query = "SELECT * FROM " + TableName + " WHERE " + dbfield + "= ?";
Cursor cursor = db.rawQuery(query, new String[] { fieldValue });
Instead of doing a query every time you want to insert, why not make the TITLE_SI column UNIQUE with ON CONFLICT IGNORE or ONC CONFLICT REPLACE? Then you don't need to check, you simply insert and let the uniqueness constraint manage this for you.
I'm running an update query that compiles. But when I test the results, there seem to be no changes. Everything looks good to me, but clearly something is wrong. Can anyone see what I am missing. Pretty new to SQLite, so apologies if it's something simple. Thanks!
public static Boolean updateHealth (int unitVal, int oldValue, int newValue) {
String unit = Integer.toString(unitVal);
String oldVal = Integer.toString(oldValue);
String newVal = Integer.toString(newValue);
System.err.printf("old val: %s, new val: %s\n", oldVal, newVal);
SQLiteDatabase db = myDBOpenHelper.getWritableDatabase();
String where = UNIT_COLUMN + " = " + unit + " AND " + HEALTH_COLUMN + " = " + oldVal;
Cursor cursor = db.query(UNITS_TABLE, new String[] {UNIT_COLUMN}, where, null, null, null, null);
if (cursor != null) {
/* the record doesn't exist, cancel the operation */
return false;
}
ContentValues updatedValues = new ContentValues();
updatedValues.put(HEALTH_COLUMN, newVal);
/* SQL query clauses */
String whereArgs[] = null;
db.update(UNITS_TABLE, updatedValues, where, whereArgs);
return true;
}
The cursor is not null when no row is retrieved. So you have to replace the line if (cursor != null) { by if(!cursor.moveToNext()) {
By the way, you don't need to query the database before updating. You can do the update, see how many rows have been affected and return true if the number of affected rows is > 0, false otherwise. The number of affected rows is returned by the method update.
This question already has an answer here:
Closed 10 years ago.
Possible Duplicate:
Fetch data in database table insert it if not exist else return the row id
I try to fetch if data exist in database table, if yes I should get the row id else I insert it in the table this my code
public int finddate(String date){
int id=0;
AndroidOpenDbHelper androidOpenDbHelperObj = new AndroidOpenDbHelper(this);
SQLiteDatabase sqliteDatabase = androidOpenDbHelperObj.getWritableDatabase();
Cursor cursor = sqliteDatabase.rawQuery("SELECT _id FROM " +
AndroidOpenDbHelper.TABLE_DATE + " where " +
AndroidOpenDbHelper.COLUMN_NAME_DATE + " = " + date,
null);
startManagingCursor(cursor);
if (cursor != null) {
if( cursor.moveToFirst() ) {
id = cursor.getInt(cursor.getColumnIndex("_id"));
}
} else {
id=0;
}
sqliteDatabase.close();
return id;
}
when i try with an existing item I get the result of this method =0 and the item is inserted in the table,
how can I do this?
The date is not being correctly escaped. The safest and cleanest way to resolve it is to pass the date value as a parameter, rather than embedding it in the query.
You can also tidy up the cursor management quite a bit. You don't need to check for a null cursor, as an exception will be thrown if the query fails. Also, you don't need to set id = 0 as you've already done that at the start. This is much simpler:
Cursor cursor = sqliteDatabase.rawQuery("SELECT _id FROM " +
AndroidOpenDbHelper.TABLE_DATE + " where " +
AndroidOpenDbHelper.COLUMN_NAME_DATE + " = ?",
new String[] { date } );
if ( cursor.moveToFirst() ) {
id = cursor.getInt(cursor.getColumnIndex("_id"));
}
cursor.close();
sqliteDatabase.close();
Your query should look like this:
Cursor cursor = sqliteDatabase.rawQuery("SELECT _id FROM " + AndroidOpenDbHelper.TABLE_DATE + " where "+ AndroidOpenDbHelper.COLUMN_NAME_DATE+ " =\'"+date+"\'", null);
startManagingCursor(cursor);
cursor.moveTofirst();
if (cursor.getCount() > 0) {
id = cursor.getInt(cursor.getColumnIndex("_id"));
}
} else {
id=0;
}
Is there a nice way in Android to see if a column exists in a table in the application database? (I know there are questions similar to this one already, but there don't seem to be any that are Android specific.)
cursor.getColumnIndex(String columnName) returns -1 if, the column doesn't exist. So I would basically perform a simple query like "SELECT * FROM xxx LIMIT 0,1" and use the cursor to determine if the column, you are looking for, exists
OR
you can try to query the column "SELECT theCol FROM xxx" and catch an exception
My function based on #martinpelants answer:
private boolean existsColumnInTable(SQLiteDatabase inDatabase, String inTable, String columnToCheck) {
Cursor mCursor = null;
try {
// Query 1 row
mCursor = inDatabase.rawQuery("SELECT * FROM " + inTable + " LIMIT 0", null);
// getColumnIndex() gives us the index (0 to ...) of the column - otherwise we get a -1
if (mCursor.getColumnIndex(columnToCheck) != -1)
return true;
else
return false;
} catch (Exception Exp) {
// Something went wrong. Missing the database? The table?
Log.d("... - existsColumnInTable", "When checking whether a column exists in the table, an error occurred: " + Exp.getMessage());
return false;
} finally {
if (mCursor != null) mCursor.close();
}
}
Simply call:
boolean bla = existsColumnInTable(myDB,"MyTable","myColumn2check");
I actually wrote this function that seems pretty clean:
private boolean field_exists( String p_query )
{
Cursor mCursor = mDb.rawQuery( p_query, null );
if ( ( mCursor != null ) && ( mCursor.moveToFirst()) )
{
mCursor.close();
return true ;
}
mCursor.close();
return false ;
}
I call it like this:
if ( field_exists( "select * from sqlite_master "
+ "where name = 'mytable' and sql like '%myfield%' " ))
{
do_something ;
}
Here is my solution to the issue which adds to flexo's solution a little.
You can put this method in any class, perhaps your SQLiteOpenHelper extending class.
public static boolean columnExistsInTable(SQLiteDatabase db, String table, String columnToCheck) {
Cursor cursor = null;
try {
//query a row. don't acquire db lock
cursor = db.rawQuery("SELECT * FROM " + table + " LIMIT 0", null);
// getColumnIndex() will return the index of the column
//in the table if it exists, otherwise it will return -1
if (cursor.getColumnIndex(columnToCheck) != -1) {
//great, the column exists
return true;
}else {
//sorry, the column does not exist
return false;
}
} catch (SQLiteException Exp) {
//Something went wrong with SQLite.
//If the table exists and your query was good,
//the problem is likely that the column doesn't exist in the table.
return false;
} finally {
//close the db if you no longer need it
if (db != null) db.close();
//close the cursor
if (cursor != null) cursor.close();
}
}
If you use ActiveAndroid
public static boolean createIfNeedColumn(Class<? extends Model> type, String column) {
boolean isFound = false;
TableInfo tableInfo = new TableInfo(type);
Collection<Field> columns = tableInfo.getFields();
for (Field f : columns) {
if (column.equals(f.getName())) {
isFound = true;
break;
}
}
if (!isFound) {
ActiveAndroid.execSQL("ALTER TABLE " + tableInfo.getTableName() + " ADD COLUMN " + column + " TEXT;");
}
return isFound;
}
At the risk of just posting the same solution but shorter. Here's a cut down version based on #flexo's
private boolean doesColumnExistInTable(SupportSQLiteDatabase db, String tableName, String columnToCheck) {
try (Cursor cursor = db.query("SELECT * FROM " + tableName + " LIMIT 0", null)) {
return cursor.getColumnIndex(columnToCheck) != -1;
} catch (Exception Exp) {
// Something went wrong. we'll assume false it doesn't exist
return false;
}
}
And in Kotlin
private fun doesColumnExistInTable(db: SupportSQLiteDatabase, tableName: String, columnToCheck: String): Boolean {
try {
db.query("SELECT * FROM $tableName LIMIT 0", null).use { cursor -> return cursor.getColumnIndex(columnToCheck) != -1 }
} catch (e: Exception) {
// Something went wrong. we'll assume false it doesn't exist
return false
}
}
this is my testing code:
String neadle = "id"; //searched field name
String tableName = "TableName";
boolean found = false;
SQLiteDatabase mDb = ActiveAndroid.getDatabase();
Cursor mCursor = mDb.rawQuery( "SELECT * FROM sqlite_master WHERE name = '"+tableName+"' and sql like '%"+neadle+"%'" , null);
mCursor.moveToFirst();
String fie = ",";
if (mCursor.getCount() > 0) {
String[] fields = mCursor.getString(mCursor.getColumnIndex("sql")).split(",");
for (String field: fields) {
String[] fieldNameType = field.trim().split(" ");
if (fieldNameType.length > 0){
fie += fieldNameType[0]+",";
}
}
}else {
//table not exist!
}
if (mCursor != null) mCursor.close();
// return result:
found = fie.contains(","+neadle+",");