I am trying to check if a value is in SQLite with python to then either update the table if the value exists or create a new value if it is not. I have tried to create a cursor to check rows, append the rows to a list with loop, check if value exists, check the count of the rows... I seems to get hung up on the if statement when trying to access the value initialized from the query. Here is the code:
checkT = db.execute("SELECT COUNT(*) FROM trans WHERE stock=:stock AND id=:user_id", stock=request.form.get("symbol"), user_id=session["user_id"])
if checkT > 0:
print("there")
else:
print("not there")
How can I fix this? Thank you!
From the CS50 Library for Python doc for execute
Returns
for SELECTs, a list of dict objects, each of which represents a row in the result set; for INSERTs, the primary key of a newly inserted row (or None if none); for UPDATEs, the number of rows updated; for DELETEs, the number of rows deleted; for CREATEs, True on success; on error, a RuntimeError is raised
checkT is a list with one element, which is a dict with one key/value pair.
This checkT[0]['COUNT(*)'] will give the number returned from the sql. Counting the rows would not be appropriate in this case because this query will always return one row.
One hint: column names in a SELECT can be aliased, given a different name, like so:
SELECT COUNT(*) as count from....... It would just be typing convenience, because then the key in the returned dict will be count instead of COUNT(*).
Remember: in the flask run terminal there is a traceback with gives more details information on the error received (assuming "hung up" means a 500 Internal Server Error).
Related
Is there a way to get the index of the results within an aql query?
Something like
FOR user IN Users sort user.age DESC RETURN {id:user._id, order:{index?}}
If you want to enumerate the result set and store these numbers in an attribute order, then this is possible with the following AQL query:
LET sorted_ids = (
FOR user IN Users
SORT user.age DESC
RETURN user._key
)
FOR i IN 0..LENGTH(sorted_ids)-1
UPDATE sorted_ids[i] WITH { order: i+1 } IN Users
RETURN NEW
A subquery is used to sort users by age and return an array of document keys. Then a loop over a numeric range from the first to the last index of the that array is used to iterate over its elements, which gives you the desired order value (minus 1) as variable i. The current array element is a document key, which is used to update the user document with an order attribute.
Above query can be useful for a one-off computation of an order attribute. If your data changes a lot, then it will quickly become stale however, and you may want to move this to the client-side.
For a related discussion see AQL: Counter / enumerator
If I understand your question correctly - and feel free to correct me, this is what you're looking for:
FOR user IN Users
SORT user.age DESC
RETURN {
id: user._id,
order: user._key
}
The _key is the primary key in ArangoDB.
If however, you're looking for example data entered (in chronological order) then you will have to have to set the key on your inserts and/or create a date / time object and filter using that.
Edit:
Upon doing some research, I believe this link might be of use to you for AI the keys: https://www.arangodb.com/2013/03/auto-increment-values-in-arangodb/
we need create custom last evaluated key
The use case goes Here:
First scan table its having ten records,the tenth record should my last evaluated key when i do second time scan operation
Thanks in advance
#Exclusive start key should be null for your first page
esk = None
#Get the first page
scan_generator = MyTable.scan(Limit=10, exclusive_start_key=esk)
#Get the key for the next page
esk = scan_generator.kwargs['exclusive_start_key'].values()
#Now get page 2
scan_generator = MyTable.scan(Limit=10, exclusive_start_key=esk)
EDIT:
exclusive_start_key (list or tuple) – Primary key of the item from which to continue an earlier query. This would be provided as the LastEvaluatedKey in that query.
For example
exclusive_start_key = ('myhashkey');
or
exclusive_start_key = ('myhashkey', 'myrangekey');
I am trying to reference dynamic tables and fields in a tkinter GUI project using MySQLdb. Using psycopg2.sql to handle an insert statement.
The user select a code, size and color and inputs a quantity. The table names are made up of the size and the code (eg. size-small and code-1111, table_name=small1111). Then the color is the column name and the quantity is an integer entered into the field. The inputs are saved in a dictionary (tdict) when the user selects them. And the dictionary elements are called to be saved in the database table.
table_name = tdict['Size']+tdict['Code']
stmnt = ("INSERT INTO {} (%s, Date) VALUES(%s, %s)").format(sql.Identifier((table_name, tdict['Color'])))
c.execute(sql.SQL(stmnt, (tdict['Quantity'], date)))
The insert query is giving me a TypeError
TypeError("SQL identifiers must be strings")
Can anyone please help? What am I doing wrong? How should the Identifier be made to behave as a string?
Note: I've tried to pass the Identifier elements through a str class but it didn't work. ie
stmnt = ("INSERT INTO {} (%s, Date) VALUES(%s, %s)").format(sql.Identifier((str(table_name, tdict['Color']))))
You are asking sql.Identifier() to create an identifier out of a tuple, e.g. ('small1111','magenta'). Because format() only substitutes into braces {} (and not %s), I think what you actually had in mind was this:
stmnt = sql.SQL("INSERT INTO {} ({}, Date) VALUES(%s %s)").format( sql.Identifier(table_name), sql.Identifier(tdict['Color']) )
I'd suggest you rethink your database design, though --- you should probably have columns named size, code, and color rather than separate tables and columns for each. That will prevent you from having to add a new column each time a new color or a new table for each new size or code. SELECT count(*) FROM inventory WHERE size = 'small' AND code = '1111' GROUP BY color seems preferable to having to create queries dynamically.
This error message will also appear when you have a typo error where you should have used sql.Literal('someFixedNumber'), but instead using sq.Identifier('someFixedNumber')
I've got a problem that I don't know how to solve, I've tried many solutions but always getting that Operational error: near...
def insert_medicine_to_table():
con = sqlite3.connect('med_db3.db')
cur = con.cursor()
table_name = 'medicines'
column_name = "présentation"
value = 'Boîte de 2 seringues pré-remplies'
cur.execute("INSERT INTO medicines {} VALUES (?)".format(column_name), value)
con.commit()
con.close()
sqlite3.OperationalError: near "présentation": syntax error
The goal here is that either the script or python has to recognize the field (column name) and insert the value into "that" field, like the following:
fields = ['présentation', 'princeps', 'distributeur_ou_fabriquant', 'composition', 'famille', 'code_atc', 'ppv', 'prix_hospitalier', 'remboursement', 'base_de_remboursement__ppv', 'nature_du_produit']
values = ['Boîte de 2 seringues pré-remplies', 'Oui', 'SANOFI', 'Héparine', 'Anticoagulant héparinique', 'B01AB01', '43.80', '27.40', 'Oui', '43.80', 'Médicament']
That is one entry in the database. The problem here is that other entries can or not have one or more values for some field, and also the fields are not presented in the same order in other entries.
It has to recognize each field in the database table and insert each value into the right column.
The problem causing your error is that your SQL isn't valid. The statement you are trying to execute is:
INSERT INTO medicines présentation VALUES (?)
The statement you want to execute is:
INSERT INTO medicines ("présentation") VALUES (?)
As far as your larger question is concerned, if you create both the list of columns ("présentation") and list of parameter markers (?) and build the query using them, you're most of the way there.
If a field can have multiple values supplied for each "entry" in your database, you may need to change your database design to handle that. You'll at least need to figure out how you want to handle the situation, but that would be a matter for a different question.
I'm trying to populate two different QTableWidgets. For the first one it works find, but for the second one, it won't actaully set the items to the QTableWidget.
In the second, failing attempt, it does successfully create the item (both type(item) and item.text() work fine and return the correct values). However, when I try to add the item to the table, it says that table2.item(row, col) is NoneType. The rows and columns are created correctly before setting the item though.
working attempt:
item = QTableWidgetItem(self.fields[j].name())
item.setFlags(Qt.ItemIsSelectable | Qt.ItemIsEnabled)
table1.setItem(j,i,item)
failing attempt:
item = QTableWidgetItem(typ)
item.setFlags(Qt.ItemIsSelectable | Qt.ItemIsEnabled)
table2.setItem(row, col, item)
Neither can I see the difference between the two blocks, nor do I understand why it won't set the item to the TableWidget. Is there a geneal misunderstandng about how this works?