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')
Related
I have a database from which data is coming into a QTableWidget. The table in the database has the following Columns,
ID (Primary key, auto-increment value)
Name
Location
The QTableWidget has the following columns (that I have added)
ID (this column, I have hidden. and it contains the value of "ID" column from the Database Table)
Sr # (Represents the Row Number of the table)
Name (Contains "name" from the database table)
Location (Contains "Location from the database table)
Actions (Contains a Delete Button for that Row)
By hidden, I mean to say that I have made this column hidden using the folliwng command,
self.ui.table.setColumnHidden(0, True);
This is how I am populating my QTableWidget and creating a Delete Function,
def get_data(self):
mycursor = self.DB.cursor()
Subquery = "select id, name, location "
Subquery += " from tbl_person"
mycursor.execute(Subquery)
numcols = len(mycursor.fetchall()[0])
mycursor.execute(Subquery)
numrows = len(mycursor.fetchall())
self.ui.table.setRowCount(numrows)
self.ui.table.setColumnCount(numcols+2)
mycursor.execute(Subquery)
tablerow = 0
for row in mycursor.fetchall():
layout = QHBoxLayout()
layout.setContentsMargins(0, 0, 0, 0)
layout.setSpacing(0)
delete_button = QPushButton("Delete Data")
delete_button.clicked.connect(self.executeDeleteFunction)
# delete_button.setStyleSheet(delete_push_button) -> Only for styling
self.ui.table.setItem(tablerow, 0, PySide2.QtWidgets.QTableWidgetItem(str(row[0])))
self.ui.table.setItem(tablerow, 1, PySide2.QtWidgets.QTableWidgetItem(str(tablerow+1)))
self.ui.table.setItem(tablerow, 2, PySide2.QtWidgets.QTableWidgetItem(str(row[1])))
self.ui.table.setItem(tablerow, 3, PySide2.QtWidgets.QTableWidgetItem(str(row[2])))
self.ui.table.setCellWidget(tablerow, 4, delete_button)
tablerow += 1
self.ui.table.setColumnHidden(0, True)
#self.ui.registered_table.horizontalHeader().setSectionResizeMode(PySide2.QtWidgets.QHeaderView.Stretch)
self.ui.table.resizeColumnsToContents()
def executeDeleteFunction(self):
self.person_id = self.ui.table.selectionModel().selectedIndexes()[0]
self.person_id = self.person_id.row()
mycursor = self.DB.cursor()
sql = "delete from tbl_person where id = %s"
val = (id, )
mycursor.execute(sql, val)
print("Deletion Successful")
On the Deletion Function, what this code does is basically gets the value of the **Sr # ** Column from the QTableWidget and deletes the data according to that, i.e. it is getting me the value from the visible first column and not the actual first column. But, I want the data from the "ID" column of the QTableWidget which is hidden
I tried to look up on how to get the value from the first hidden column on the QTableWidget and ended up with this link: How to get data from hidden 'id' column in QtableWidget
This apparently solves my issue but I can not seem to make it work for my code. I don't want to retrieve values of multiple Rows but only of one row so how do I do this (as I am only deleting one row. But in the question mentioned, I believe that it is getting data from multiple rows due to that for each loop)?
Moreover, I tried to find help regarding the functionality of sibling function (which is provided in the answer of above question) however I could not find any good resource on this function (i.e. how to use this, or some practical example and etc.)
I tried the following with Sibling function to obtain the value of first hidden column of the Selected Row but it did not work,
self.value = self.table.selectedItems()[0]
self.value = sibling(self.value.row(), 0)
There are some conceptual problems with the given code.
First of all, the QtSql module should be preferred instead of artificially creating a model. For basic tables, QSqlTableModel is fine enough, while for custom queries, QSqlQueryModel is a good choice.
Now the problem is that UI-based selection is always based on visible items: if you select a row in a view that has hidden columns, you will not get the hidden indexes that belong to those columns.
In order to get the indexes (as in QModelIndex) of hidden columns on a table widget, the only way is the same for a table view: you need to access the model and get the index for the row, or you get the actual model index and then get the sibling (which is conceptually the same, as the underlying function does):
item = self.table.selectedItems()[0]
index = self.table.indexForItem(index)
firstRowIndex = index.sibling(index.row(), 0)
sqlIndex = firstRowIndex.data() # might be a string
Note that you can also use siblingAtColumn():
firstRowIndex = index.siblingAtColumn(0)
That's because when you create QTableWidget items, you're actually creating a new model, and the row for that model doesn't reflect the actual "row" of that index in the source model; items in the second row will return 1 for row(), even if their actual row is different, and that's because that item has been added as second to the table widget, since it's the second item in the query.
So, the solution is that you either get the incremental row value for the first column index sibling, or you use one of the predefined Sql models.
For simple models, the latter solution is fine enough, but if you need more complex models, the first is certainly more accurate and reliable.
like the title mentions I want a Query that gets a random row of the existing database. After that I want to save the data which is in a specific column of that row in a variable for further purposes.
The query I have at the moment is as follows:
#Query("SELECT * FROM data_table ORDER BY RANDOM() LIMIT 1")
fun getRandomRow()
For now I am not sure if this query even works, but how would I go about writing my function to pass a specific column of that randomly selected row to a variable?
Ty for your advice, tips and/or solutions!
Your query is almost correct; however, you should specify a return type in the function signature. For example, if the records in the data_table table are mapped using a data class called DataEntry, then the query could read as shown below (note I've also added the suspend modifier so the query must be run using a coroutine):
#Query("SELECT * FROM data_table ORDER BY RANDOM() LIMIT 1")
suspend fun getRandomRow(): DataEntry?
If your application interacts with the database via a repository and view model (as described here: https://developer.android.com/topic/libraries/architecture/livedata) then the relevant methods would be along the lines of:
DataRepository
suspend fun findRandomEntry(): DataEntry? = dataEntryDao.getRandomRow()
DataViewModel
fun getRandomRecord() = viewModelScope.launch(Dispatchers.IO) {
val entry: DataEntry? = dataRepository.findRandomEntry()
entry?.let {
// You could assign a field of the DataEntry record to a variable here
// e.g. val name = entry.name
}
}
The above code uses the view model's coroutine scope to query the database via the repository and retrieve a random DataEntry record. Providing the returning DataEntry record is not null (i.e. your database contains data) then you could assign the fields of the DataEntry object to variables in the let block of the getRandomRecord() method.
As a final point, if it's only one field that you need, you could specify this in the database query. For example, imagine the DataEntry data class has a String field called name. You could retrieve this bit of information only and ignore the other fields by restructuring your query as follows:
#Query("SELECT name FROM data_table ORDER BY RANDOM() LIMIT 1")
suspend fun getRandomRow(): String?
If you go for the above option, remember to refactor your repository and view model to expect a String instead of a DataEntry object.
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).
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 have two tables. Both of them have a column named 'title'. When I use the following code snippet to join two tables, I can't access one of the title column.
$select = $this->select(Zend_Db_Table::SELECT_WITH_FROM_PART);
$select->setIntegrityCheck(false);
$select->join("service","service.id = lecture.service_id");
return $select;
is there a way to access both columns?
You need to rename one of the columns so it doesn't conflict with the other. If you pass an array as the optional 3rd argument to join(), you can specify which columns to retrieve from the joined table. If one or more of the entries in the array is hashed, then the hash key will be used as the property name. With the code below, you can refer to the title column of the service table as "service_title" in your query results. If you want other columns from the service table, add them to the array, with or without hashes as desired.
$select = $this->select(Zend_Db_Table::SELECT_WITH_FROM_PART);
$select->setIntegrityCheck(false);
$select->join("service", "service.id = lecture.service_id",
array("service_title" => "service.title");
return $select;
$select = $this->select();
$select->from(array('t'=>'table1'), array('table_title AS title_first','table_sendo_colun','table_third_colun'));
$select->setIntegrityCheck(false);
$select->join("service","service.id = t.service_id");
return $select;
Maybe It can do the job.
Regard´s.