I have to connect to an Oracle database and see if a table exists. While I can get a list of the tables, I'm having trouble seeing if the table I'm looking for is in the list. Some tables have associated table which I'll have to join on, some do not, thus I have to check.
What is in my list: ('NYSDOH_CI_EI_HOSPITAL',)
sql = "SELECT table_name FROM all_tables"
cur.execute(sql)
searchstr = 'NYSDOH_CI_EI_HOSPITAL'
p = re.compile(searchstr)
#create data array to load in SQL results in.
ciDataSet = []
cxRows = cur.fetchall()
for i in cxRows:
#print i # list of tables
if p.match(str(i)):
print i
It doesn't find it, even if I use a wildcard.
fetchall() returns a list of tuples.
So when you do
for i in cxRows:
'i' is of type tuple. In your case, this tuple will have only single value. You can access it using i[0] and match it with p.
Currently you are converting a tuple to string so regular expression will not match.
Corrected code:
sql = "SELECT table_name FROM all_tables"
cur.execute(sql)
searchstr = 'NYSDOH_CI_EI_HOSPITAL'
p = re.compile(searchstr)
#create data array to load in SQL results in.
ciDataSet = []
cxRows = cur.fetchall()
for i in cxRows:
#print i # list of tables
if p.match(str(i[0])):
print i
To improve on the syntax of #vaichidrewar, you could simplify the fetch loop to:
for tabname, in cur:
if p.match(str(tabname)):
print(tabname)
But it's going to be more efficient to do the reg exp matching in the query:
sql = "select table_name from all_tables where regexp_like(table_name, :tn, 'i')"
searchstr = 'EMP'
cur.execute(sql, (searchstr,))
for tabname, in cur:
print(tabname)
The 'i' option does a case-insensitive match. You can adjust the regexp as you like.
Related
I have tried to query all elements from a list into an insertion query, I tried by making the list into a list of tuples and directly by adding the elements from the list. But it did not work, and I don't know the best practice for this as I am no SQL shark. I have below added the two different outputs I have before I do the query. I don't know which is easier to work with for this, but the code example is for the list of elements.
Output
['testuser', 'AskeMeyer']
and
[('testuser',), ('AskeMeyer',)]
Code to query
try:
conn = psycopg2.connect(host=ENDPOINT, port=PORT, database=DBNAME, user=USER, password=PASS, sslmode='require', sslrootcert="SSLCERTIFICATE")
cur = conn.cursor()
var_string = ', '.join(map(str, res))
sql = 'INSERT INTO users_from_group(name) VALUES %s;' % var_string)
cur.execute(sql)
error from above
Database connection failed due to syntax error at or near ")"
You need to use brackets and quotes in your insert statement, for example:
var_string = ', '.join([f"(\"{name}\")" for name in ['testuser', 'AskeMeyer']])
Also, there is a bracket at the end of your sql statement which causes the syntax error:
sql = 'INSERT INTO users_from_group(name) VALUES %s;' % var_string)
Should be
sql = 'INSERT INTO users_from_group(name) VALUES %s;' % var_string
it's not the proper way to store lists.
you should save it as json :
json.dumps(['testuser', 'AskeMeyer'] )
then save it
Try this:
var_string = '(' + ','.join(map(str, res)) + ')'
sql = 'INSERT INTO users_from_group(name) VALUES %s;' % var_string
Saving a string into a sqlite table, retrieving it again and comparing it to the original requires some filters to work and i dont know why exactly.
tl;dr
How can i retrieve string Data from the SQLITE DB without requiring Filter Nr 3 as its dangerous for more complex strings ?
import sqlite3
RAWSTRING = 'This is a DB Teststing'
# create database and table
currentdb = sqlite3.connect('test.db')
currentdb.execute('''CREATE TABLE tickertable (teststring text)''')
# enter RAWSTRING into databasse
currentdb.execute('''INSERT INTO tickertable VALUES(?);''', (RAWSTRING,))
# get RAWSTRING from database
cursorObj = currentdb.cursor()
cursorObj.execute('SELECT * FROM tickertable')
DB_RAWSTRING = cursorObj.fetchall()
currentdb.commit()
currentdb.close()
# Prints This is a DB Teststing
print('originalstring : ', RAWSTRING)
# Prints [('This is a DB Teststing',)]
print('retrieved from DB: ', DB_RAWSTRING)
# Get first entry from List because fetchall gives a list
FILTER1_DB_RAWSTRING = DB_RAWSTRING[0]
# Convert the Listelement to String because its still a listelement and comparing fails to string
FILTER2_DB_RAWSTRING = str(FILTER1_DB_RAWSTRING)
# Remove annoying db extra characters and i dont know why they exist anyway
FILTER3_DB_RAWSTRING = FILTER2_DB_RAWSTRING.replace("'", "").replace("(", "").replace(")", "").replace(",", "")
if RAWSTRING == FILTER3_DB_RAWSTRING:
print('Strings are the same as they should')
else:
print('String are not the same because of db weirdness')
So here's your problem: fetchall returns a list of tuples. This means that casting them to a string puts pesky parenthesis around each row and commas between each element of each row. If you'd like to retrieve the raw information from each column, that can be done by indexing the tuples:
entries = cursorObj.fetchall()
first_row = entries[0]
first_item = first_row[0]
print(first_item)
This ought to print just the content of the first row and column in the DB. If not, let me know!
David
I am using the below code to delete a row from sqlite table.
def deleteFromTable(item):
conn = sqlite3.connect("lite.db")
cur = conn.cursor()
cur.execute("DELETE FROM store WHERE item=?", (item,))
conn.commit()
conn.close()
Why do i need to use comma after item (item,) while passing the argument?
('String') evaluates into string, but ('string',) evaluates into tuple. that's why you need comma.
I'm looking to take an array list and attach it to a string.
Python 2.7.10, Windows 10
The list is loaded from a mySQL table and the output is this:
skuArray = [('000381001238',) ('000381001238',) ('000381001238',) ('FA200513652',) ('000614400967',)]
I'm wanting to take this list and attach it to a separate query
the problem:
query = "SELECT ItemLookupCode,Description, Quantity, Price, LastReceived "
query = query+"FROM Item "
query = query+"WHERE ItemLookupCode IN ("+skuArray+") "
query = query+"ORDER BY LastReceived ASC;"
I get the error:
TypeError: cannot concatenate 'str' and 'tuple' objects
My guess here is that I need to format the string as:
'000381001238', '000381001238', '000381001238', 'FA200513652','000614400967'
Ultimately the string needs to read:
query = query+"WHERE ItemLookupCode IN ('000381001238', '000381001238', '000381001238', 'FA200513652','000614400967') "
I have tried the following:
skuArray = ''.join(skuArray.split('(', 1))
skuArray = ''.join(skuArray.split(')', 1))
Second Try:
skus = [sku[0] for sku in skuArray]
stubs = ','.join(["'?'"]*len(skuArray))
msconn = pymssql.connect(host=r'*', user=r'*', password=r'*', database=r'*')
cur = msconn.cursor()
query ='''
SELECT ItemLookupCode,Description, Quantity, Price, LastReceived
FROM Item
WHERE ItemLookupCode IN { sku_params }
ORDER BY LastReceived ASC;'''.format(sku_params = stubs)
cur.execute(query, params=skus)
row = cur.fetchone()
print row[3]
cur.close()
msconn.close()
Thanks in advance for your help!
If you want to do the straight inline SQL you could use a list comprehension:
', '.join(["'{}'}.format(sku[0]) for sku in skuArray])
Note: You need to add commas between tuples (based on example)
That said, if you want to do some sql, I would encourage you to parameterize your request with ?
Here is an example of how you would do something like that:
skuArray = [('000381001238',), ('000381001238',), ('000381001238',), ('FA200513652',), ('000614400967',)]
skus = [sku[0] for sku in skuArray]
stubs = ','.join(["'?'"]*len(skuArray))
qry = '''
SELECT ItemLookupCode,Description, Quantity, Price, LastReceived
FROM Item
WHERE ItemLookupCode IN ({ sku_params })
ORDER BY LastReceived ASC;'''.format(sku_params = stubs)
#assuming pyodbc connection syntax may be off
conn.execute(qry, params=skus)
Why?
Non-parameterized queries are a bad idea because it leaves you vulnerable to sql injection and is easy to avoid.
Assuming that skuArray is a list, like this:
>>> skuArray = [('000381001238',), ('000381001238',), ('000381001238',), ('FA200513652',), ('000614400967',)]
You can format your string like this:
>>> ', '.join(["'{}'".format(x[0]) for x in skuArray])
"'000381001238', '000381001238', '000381001238', 'FA200513652', '000614400967'"
This code is writing only one row in DB
I find no error in this code . . .
But why is this not inserting more than the first row ?
def transremovechars():
cur.execute('drop table transforms')
char_cfg = config.get('Transform_Variables', 'Chars_to_be_removed') #Reads all the special chars to be removed from specialchars.txt#
cur.execute('select * from originallist')
for row in cur: #Applies transformation to remove chars for each row in a loop#
company = row[0]
for specialchars in char_cfg:
company = company.replace(specialchars, '')
cur.execute('Insert into transforms (Transresult1) values (\'' + company + '\')')
con.commit()
You forgot the cur.fetchall():
def transremovechars():
cur.execute('drop table transforms')
char_cfg = config.get('Transform_Variables', 'Chars_to_be_removed') #Reads all the special chars to be removed from specialchars.txt#
cur.execute('select * from originallist')
for row in cur.fetchall(): #Applies transformation to remove chars for each row in a loop#
company = row[0]
for specialchars in char_cfg:
company = company.replace(specialchars, '')
cur.execute('Insert into transforms (Transresult1) values (\'' + company + '\')')
con.commit()
You seem to drop your table transforms before working with it. Are you sure you want that? Or maybe have you forgotten to show the code which creates it again?
Your select * might e overkill if you only use the 1st column. Maybe you want to name that field in the SELECT.
Besides, you should replace your INSERT line with
cur.execute('Insert into transforms (Transresult1) values (?)', company)
Iterating over the cursor should be fine, however. Maybe you could insert some print statements into your for loop...
Comments to the effect that you should cur.fetchall() and iterate over that will work and be OK. The real fault in your code is that once you use cur to insert, it is a "new thing" and the original generator is reset (cur has the next()) method.
You can use cur without doing fetchall as you wanted, just create a second cursor ins_cur = con.curson() and use both. Many more advanced effects can be accomplished by iterating or using multiple cursors open on one connection.
And yes please use the correct variable binding for your dbapi module.