Check if a column exists in SQLite

Question

I need to check to see if a column exists and if it doesn\'t exist add it. From my research it looks like sqlite doesn\'t support IF statements and case statement should be

Answer 1

Update the DATABASE_VERSION so onUpgrade function is called then if Column is already exists then nothing happen if not then it will add new column.

 private static class OpenHelper extends SQLiteOpenHelper {

OpenHelper(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {
}

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


    if (!isColumnExists(db, "YourTableName", "YourColumnName")) {

        try {

            String sql = "ALTER TABLE " + "YourTableName" + " ADD COLUMN " + "YourColumnName" + "TEXT";
            db.execSQL(sql);

        } catch (Exception localException) {
            db.close();
        }

    }


}

}

 public static boolean isColumnExists(SQLiteDatabase sqliteDatabase,
                                     String tableName,
                                     String columnToFind) {
    Cursor cursor = null;

    try {
        cursor = sqliteDatabase.rawQuery(
                "PRAGMA table_info(" + tableName + ")",
                null
        );

        int nameColumnIndex = cursor.getColumnIndexOrThrow("name");

        while (cursor.moveToNext()) {
            String name = cursor.getString(nameColumnIndex);

            if (name.equals(columnToFind)) {
                return true;
            }
        }

        return false;
    } finally {
        if (cursor != null) {
            cursor.close();
        }
    }
}

Answer 2

I updated the function of a friend... tested and working now

    public boolean isFieldExist(String tableName, String fieldName)
{
    boolean isExist = false;
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor res = db.rawQuery("PRAGMA table_info(" + tableName + ")", null);


    if (res.moveToFirst()) {
        do {
            int value = res.getColumnIndex("name");
            if(value != -1 && res.getString(value).equals(fieldName))
            {
                isExist = true;
            }
            // Add book to books

        } while (res.moveToNext());
    }

    return isExist;
}

Answer 3

I am really sorry for posting it late. Posting in the intention of may be helpful in someone's case.

I tried fetching the column from the database. If it returns a row, it contains that column otherwise not...

-(BOOL)columnExists { 
 BOOL columnExists = NO;

//Retrieve the values of database
const char *dbpath = [[self DatabasePath] UTF8String];
if (sqlite3_open(dbpath, &database) == SQLITE_OK){

    NSString *querySQL = [NSString stringWithFormat:@"SELECT lol_10 FROM EmployeeInfo"];
    const char *query_stmt = [querySQL UTF8String];

    int rc = sqlite3_prepare_v2(database ,query_stmt , -1, &statement, NULL);
    if (rc  == SQLITE_OK){
        while (sqlite3_step(statement) == SQLITE_ROW){

            //Column exists
            columnExists = YES;
            break;

        }
        sqlite3_finalize(statement);

    }else{
        //Something went wrong.

    }
    sqlite3_close(database);
}

return columnExists; 
}