If you don’t want to update the records, use the full version of the LIMIT clause. SELECT … FROM tweets WHERE … LIMIT 1 500 SELECT … FROM tweets WHERE … LIMIT 501 500 SELECT … FROM tweets WHERE … LIMIT 1001 500 of course, this will mean you need to keep track of which … Read more
Include a flag column in the user table to indicate the user’s status, then build views on top of this against which you run your actual queries. Maybe something like this: create table users ( …. is_active boolean not null ); create view active_users as select * from users where is_active = true; create view … Read more
You can use inner join to get price for each product in orders table: Select o.customer_id, p.product_id, o.quantity, p.price from PRICES p inner join ORDERS o on p.product_id=o.product_id solved How to join each order with its price? [closed]
Indeed, that’s the way sessions typically work. Once a page is loaded, there’s no connection between the browser and the server anymore. Basically, once a page has finished loading and is just sitting there in the browser, it’s already the same as if the user had closed the window. There’s no way to 100% reliably … Read more
Steps Get the user – ideally you want to use the userid (or primary key) to retrieve the user Remove the user from the db Save the changes in the context Code: var user = db.Users.Single(x => x.Nom == formUser.Nom && x.prenom == formuser.prenom); db.Users.Remove(user); db.SaveChanges(); solved asp net. How to remove data from a … Read more
To create files, you will be using the System.IO.File namespace. This gives you access to methods such as Create(), CreateText(), WriteAllBytes(). Which method you use will depend on what type of data you are using. To save the file in your application directory, you can get the path using AppDomain.BaseDirectory So for example if you’re … Read more
Short answer is db.create_all(). Here is a piece of this answer app = Flask(__name__) app.config[‘SQLALCHEMY_DATABASE_URI’] = ‘postgresql+psycopg2://login:pass@localhost/flask_app’ db = SQLAlchemy(app) db.create_all() db.session.commit() solved sqlalchemy create tables [closed]
No. The block as a whole will get rolled back on failure, but the raise statement on its own does not perform a rollback. For example, this block fails and is implicitly rolled back (exactly as if it was an SQL insert etc): begin insert into demo(id) values(1); dbms_output.put_line(sql%rowcount || ‘ row inserted’); raise program_error; … Read more
You should join two tables using ‘inner join’ and you have to use a ‘where’ condition. In where condition use ‘AND’ to check its the same person using the employee id and then sum the total working hours. solved database view creation issue
Efficiency can mean many things. Maintainability and scalability are as important as pure performance when you design a solution. Method 2 depends on files on disk which means that in a production environment with multiple servers (which every prod env should have) you will have to keep the files in sync between all servers in … Read more
Please, don’t mix mysqli and mysql as they are different modules. In your second code block you are using mysql_select_db and mysql_error, the first one requires mysql connection, not mysqli connection. 1 solved use mysqli_connect and mysql_select_db [duplicate]
What would be the sense of 240? Tinyint is mostly represented as one byte. In all computers build since the 8 bit byte became standard that is a value of 0-255. 1 solved What is the maximum value of a “tinyint” field in most database systems? [closed]
How do you represent the linkage of a person to a team. Do you use a teamID field in person? If so, what do you do when a person is not on a team? Keep it null? select * from person where teamID is null Set it to -1? select * from person where teamID … Read more
try this, public void updateQty(Integer qty,String bookId) { int originalQty = getQuantity(bookId); int updateQty = originalQty – qty; try{ SQLiteDatabase db = this.getWritableDatabase(); String rawQuery = “update ” + BOOKS_TABLE + ” set ” + KEY_QTY + ” = ” + updateQty + ” where ” + KEY_BOOK_ID + ” = ‘” + bookId + … Read more
Yes, It is possible to reduce query time using view because it have clustered index assigned and they’ll store temporary result that can speed up resulting queries. 2 solved MySQL View is faster or not for querying from DB that containd 40 million data [closed]