I have a list contains many lists in python.
my_list = [['city', 'state'], ['tampa', 'florida'], ['miami','florida']]
The nested list at index 0 contains the column headers, and rest of the nested lists contain corresponding values. How would I insert this into sql server using pyodbc or slqalchemy? I have been using pandas pd.to_sql and want to make this a process in pure python. Any help would be greatly appreciated.
expected output table would look like:
city |state
-------------
tampa|florida
miami|florida
Since the column names are coming from your list you have to build a query string to insert the values. Column names and table names can't be parameterised with placeholders (?).
import pyodbc
conn = pyodbc.connect(my_connection_string)
cursor = conn.cursor()
my_list = [['city', 'state'], ['tampa', 'florida'], ['miami','florida']]
columns = ','.join(my_list[0]) #String of column names
values = ','.join(['?'] * len(my_list[0])) #Placeholders for values
query = "INSERT INTO mytable({0}) VALUES ({1})".format(columns, values)
#Loop through rest of list, inserting data
for l in my_list[1:]:
cursor.execute(query, l)
conn.commit() #save changes
Update:
If you have a large number of records to insert you can do that in one go using executemany. Change the code like this:
columns = ','.join(my_list[0]) #String of column names
values = ','.join(['?'] * len(my_list[0])) #Placeholders for values
#Bulk insert
query = "INSERT INTO mytable({0}) VALUES ({1})".format(columns, values)
cursor.executemany(query, my_list[1:])
conn.commit() #save change
Assuming conn is already open connection to your database:
cursor = conn.cursor()
for row in my_list:
cursor.execute('INSERT INTO my_table (city, state) VALUES (?, ?)', row)
cursor.commit()
Since the columns value are are the first elemnts in the array, just do:
q ="""CREATE TABLE IF NOT EXISTS stud_data (`{col1}` VARCHAR(250),`{col2}` VARCHAR(250); """
sql_cmd = q.format(col1 = my_list[0][0],col2 = my_list[0][1])
mcursor.execute(sql)#Create the table with columns
Now to add the values to the table, do:
for i in range(1,len(my_list)-1):
sql = "INSERT IGNORE into test_table(city,state) VALUES (%s, %s)"
mycursor.execute(sql,my_list[i][0],my_list[i][1])
mycursor.commit()
print(mycursor.rowcount, "Record Inserted.")#Get count of rows after insertion
Related
I am trying to add a new column in existing table and want to populate that column in database, there is a predictions column which is dataframe it is giving me error what I am doing wrong,
Code:
conn = create_connection()
cur = conn.cursor()
query = "ALTER TABLE STOCK_MARKET_FORECASTING ADD COLUMN predictions float"
cur.execute(query)
# Inserting predictions in database
def inserting_records(df):
for i in range(0 ,len(df)):
values = (df['Predicted_values_Hourly_Interval'][i])
cur.execute("UPDATE STOCK_MARKET_FORECASTING SET (predictions) VALUES (%s)", values)
conn.commit()
print("Records created successfully")
inserting_records(predictions)
You're passing in a single value – cur.execute requires a tuple of values.
You're probably looking for INSERT, not UPDATE. UPDATE updates existing rows.
def inserting_records(df):
series = df['Predicted_values_Hourly_Interval']
for val in series:
cur.execute("INSERT INTO STOCK_MARKET_FORECASTING (predictions) VALUES (%s)", (val, ))
conn.commit()
might be what you're looking for.
I have a database with around 10 columns. Sometimes I need to insert a row which has only 3 of the required columns, the rest are not in the dic.
The data to be inserted is a dictionary named row :
(this insert is to avoid duplicates)
row = {'keyword':'abc','name':'bds'.....}
df = pd.DataFrame([row]) # df looks good, I see columns and 1 row.
engine = getEngine()
connection = engine.connect()
df.to_sql('temp_insert_data_index', connection, if_exists ='replace',index=False)
result = connection.execute(('''
INSERT INTO {t} SELECT * FROM temp_insert_data_index
ON CONFLICT DO NOTHING''').format(t=table_name))
connection.close()
Problem : when I don't have all columns in the row(dic), it will insert dic fields by order (a 3 keys dic will be inserted to the first 3 columns) and not to the right columns. ( I expect the keys in dic to fit the db columns)
Why ?
Consider explicitly naming the columns to be inserted in INSERT INTO and SELECT clauses which is best practice for SQL append queries. Doing so, the dynamic query should work for all or subset of columns. Below uses F-string (available Python 3.6+) for all interpolation to larger SQL query:
# APPEND TO STAGING TEMP TABLE
df.to_sql('temp_insert_data_index', connection, if_exists='replace', index=False)
# STRING OF COMMA SEPARATED COLUMNS
cols = ", ".join(df.columns)
sql = (
f"INSERT INTO {table_name} ({cols}) "
f"SELECT {cols} FROM temp_insert_data_index "
"ON CONFLICT DO NOTHING"
)
result = connection.execute(sql)
connection.close()
I'm attempting to update my sqlite db with 2 python lists. I have a sqlite db with three fields. Name, number, date. I also have three python lists with similar names. I'm trying to figure out a way to update my sqlite db with data from these 2 lists. I can get the db created, and even get a single column filled, but I cant seem to update it correctly or at all. Is there a way to INSERT both lists at once? Rather than INSERT a single column and then UPDATE the db with the other?
Here is what I have so far:
name_list = []
number_list = []
date = now.date()
strDate = date.strftime("%B %Y")
tableName = strDate
sqlTable = 'CREATE TABLE IF NOT EXISTS ' + tableName + '(name text, number integer, date text)'
c.execute(sqlTable)
conn.commit()
for i in name_list:
c.execute('INSERT INTO January2018(names) VALUES (?)', [i])
conn.commit()
I can't seem to get past this point. I still need to add another list of data (number_list) and attach the date to each row.
Here's what I have on that:
for i in number_list:
c.execute('UPDATE myTable SET number = ? WHERE name', [i])
conn.commit()
Any help would be much appreciated. And if you need more information, please let me know.
You can use executemany with zip:
c.executemany('INSERT INTO January2018 (name, number) VALUES (?, ?)', zip(name_list, number_list))
conn.commit()
Admittedly I a still very new to both Python and Sqlite3, and I am attempting to add the contents of two lists into a database so that one list is in the first column and the second list shows up in the second column. To this point, I have been unsuccessful. I am defenitely making a fundamental error, and the error message that I get is this: "sqlite3.InterfaceError: Error binding parameter 0 - probably unsupported type."
my code is this:
import sqlite3
names = ['Tom', 'Dick', 'Harry']
ids = ['A452', 'B698', 'Kd9f']
conn = sqlite3.connect('testforinput.db')
c = conn.cursor()
c.execute("CREATE TABLE thetable(name TEXT, id TEXT)")
index = 0
for link in names:
idofperson = ids[index]
c.execute("INSERT INTO thetable(name, id)VALUES(?, ?)", ( [link], idofperson ))
index+=1
conn.commit()
conn.close()
The error occurs because of the for loop specifically the "idofperson" variable
The desired outcome is that I would like to have two columns created in sql one being name and the other being id.
Any help would be greatly appreciated.
I think you just change
index =0
for link in names:
idofperson = ids[index]
c.execute("INSERT INTO thetable(name, id)VALUES(?, ?)", ( [link], idofperson ))
to this (use enumrate and change [list] to list, because you pass a list into a column need TEXT type):
for index, link in enumrable(names):
idofperson = ids[index]
c.execute("INSERT INTO thetable(name, id)VALUES(?, ?)", ( link, idofperson ))
your variable index is not increasing.try using the enumerate on for loop. or just add index += 1 after execute
the error is occurring because of the unsupported data type you are trying to push in, you can't store list as it is, you need to change to another supported data types, i like this solution ....it worked for me https://stackoverflow.com/a/18622264/6180263
for your problem, try this:
import sqlite3
names = ['Tom', 'Dick', 'Harry']
ids = ['A452', 'B698', 'Kd9f']
data = zip(names, ids)
conn = sqlite3.connect('testforinput.db')
c = conn.cursor()
c.execute("CREATE TABLE thetable(name TEXT, id TEXT)")
for d in data:
sql = "INSERT INTO thetable (name, id) VALUES ('%s', '%s'); " % d
c.execute(sql)
conn.commit()
conn.close()
I suggest change data to a list of dict, like this [{'name':'Tom', 'id': 'A452'}, {'name':'dick', 'id':'B698'}..]
and you can generate insert sql by data, this make the insert more flexible.
I have constructed a database but when I loop through my data to populate it, I get the following error:
OperationalError: no such column: tmp1
Code:
with con:
cur = con.cursor()
cur.execute("CREATE TABLE TESTTABLE(X REAL, Y REAL)")
for i in xrange(0,5):
tmp1 = array[i,0]
tmp2 = array[i,1]
with con:
cur.execute("""INSERT INTO TESTTABLE VALUES(tmp1,tmp2)""")
Basically I have a big array that I want to transfer into a database. This probably isn't the most efficient way of going about it. Suggestions?
If you want to insert values into a row, you need to pass those values along as SQL parameters to the .execute() call:
with con:
for i in xrange(0,5):
tmp1 = array[i, 0]
tmp2 = array[i, 1]
cur.execute("""INSERT INTO TESTTABLE VALUES(?, ?)""", (tmp1, tmp2))
The ? characters are parameters, and they are filled, in order, by values takes from the second argument to .execute(), a tuple. The above code will insert the numbers 0 through to 4 as pairs into the database.
Names in the SQL code have no correlation to names you define in Python, values can only be passed in explicitly.