I'm using the hdbcli package to load data from SAP HANA.
Problem: When loading data, I only get the value rows without the actual headers of the SQL table.
When I load only 3 columns (as below), I can manually add them myself, even though it is very ugly. This becomes impossible when I execute a Select * statement, as I really don't want to have to add them manually and might not know when there is a change.
Question: Is there a flag / command to get the column headers from a table?
Code-MRE:
#Initialize your connection
conn = dbapi.connect(
address='00.0.000.00',
port='39015',
user='User',
password='Password',
encrypt=True,
sslValidateCertificate=False
)
cursor = conn.cursor()
sql_command = "select TITLE, FIRSTNAME, NAME from HOTEL.CUSTOMER;"
cursor.execute(sql_command)
rows = cursor.fetchall() # returns only data, not the column values
for row in rows:
for col in row:
print ("%s" % col, end=" ")
print (" ")
cursor.close()
conn.close()
Thanks to #astentx' comment I found a solution:
cursor = conn.cursor()
sql_command = "select TITLE, FIRSTNAME, NAME from HOTEL.CUSTOMER;"
cursor.execute(sql_command)
rows = cursor.fetchall() # returns only data, not the column headers
column_headers = [i[0] for i in cursor.description] # get column headers
cursor.close()
conn.close()
result = [[column_header]] # insert header
for row in rows: # insert rows
current_row = []
for cell in row:
current_row.append(cell)
result.append(current_row)
Related
I am writing a code to copy rows of matching columns from CSV to PostgreSQL table. I am using python and qgis for the same.Code is as follows
connection=psycopg2.connect(host=host, port=port, dbname=dbname, user=name_user, password=password)
cursor = connection.cursor ()
cursor.execute("""SELECT Count(*) FROM INFORMATION_SCHEMA.Columns where TABLE_NAME = 'table'""")
csv1 = pd.read_csv(self.dlg.lineEdit_5.text())
csvfile = open(self.dlg.lineEdit_5.text(),'r')
columnnames = csv1.columns.values
table=self.dlg.comboBox.currentText()
table_name = table.strip(' ' ' ')
self.dlg.lineEdit_6.setText(str(table))
with open(self.dlg.lineEdit_5.text(), 'r') as f:
reader = csv.reader(f)
next(reader) # This skips the 1st row which is the header.
for x in columnnames:
column = x.strip(' ' ' ')
#self.dlg.lineEdit_6.setText(str(column))
sql_insert = """INSERT INTO table_name(x) VALUES(%s)"""
for record in reader:
cursor.execute(sql_insert,[record])
connection.commit()
I am getting error as follows
psycopg2.errors.UndefinedTable: relation "table_name" does not exist
LINE 1: INSERT INTO table_name(x) VALUES(ARRAY['501','mah','A'])
How to resolve this error?. table_name exists in the database.
It was a silly mistake. I was taking table name from a variable in a python code. so, query need to be written as follows.
table=self.dlg.comboBox.currentText()
table_name = table.strip(' ' ' ')
sql_insert = """INSERT INTO %(table_name)s (x) VALUES(%s);"""
cursor.execute(sql_insert,[value])
connection.commit()
I'm trying to delete a row from my pysimplegui table that will also delete the same row data from my sqlite3 database. Using events, I've tried to use the index eg. -TABLE- {'-TABLE-': [1]} to index the row position using values['-TABLE-'] like so:
if event == 'Delete':
row_index = 0
for num in values['-TABLE-']:
row_index = num + 1
c.execute('DELETE FROM goals WHERE item_id = ?', (row_index,))
conn.commit()
window.Element('-TABLE-').Update(values=get_table_data())
I realized that this wouldn't work since I'm using a ROW_ID in my database that Auto-increments with every new row of data and stays fixed like so (this is just to show how my database is set up):
conn = sqlite3.connect('goals.db')
c = conn.cursor()
c.execute('''CREATE TABLE goals (item_id INTEGER PRIMARY KEY, goal_name text, goal_type text)''')
conn.commit()
conn.close()
Is there a way to use the index ( values['-TABLE-'] ) to find the data inside the selected row in pysimplegui and then using the selected row's data to find the row in my sqlite3 database to delete it, or is there any other way of doing this that I'm not aware of?
////////////////////////////////////////
FIX:
Upon more reading into the docs I discovered a .get() method. This method returns a nested list of all Table Rows, the method is callable on the element of '-TABLE-'. Using values['-TABLE-'] I can also find the row index and use the .get() method to index the specific list where the Data lays which I want to delete.
Here is the edited code that made it work for me:
if event == 'Delete':
row_index = 0
for num in values['-TABLE-']:
row_index = num
# Returns nested list of all Table rows
all_table_vals = window.element('-TABLE-').get()
# Index the selected row
object_name_deletion = all_table_vals[row_index]
# [0] to Index the goal_name of my selected Row
selected_goal_name = object_name_deletion[0]
c.execute('DELETE FROM goals WHERE goal_name = ?', (selected_goal_name,))
conn.commit()
window.Element('-TABLE-').Update(values=get_table_data())
Here is a small example to delete a row from table
import sqlite3
def deleteRecord():
try:
sqliteConnection = sqlite3.connect('SQLite_Python.db')
cursor = sqliteConnection.cursor()
print("Connected to SQLite")
# Deleting single record now
sql_delete_query = """DELETE from SqliteDb_developers where id = 6"""
cursor.execute(sql_delete_query)
sqliteConnection.commit()
print("Record deleted successfully ")
cursor.close()
except sqlite3.Error as error:
print("Failed to delete record from sqlite table", error)
finally:
if (sqliteConnection):
sqliteConnection.close()
print("the sqlite connection is closed")
deleteRecord()
In your case id will me the name of any column name which has unique value for every row in thetable of the database
I have just started learning SQLite and was creating a project which has a .sqlite file in which there are multiple tables. I want to ask the user to input the table_name and then the program will fetch the columns present in that particular table.
So far I have done this.
app_database.py
def column_names(table_name):
conn = sqlite3.connect('northwind_small.sqlite')
c = conn.cursor()
c.execute("PRAGMA table_info(table_name)")
columns = c.fetchall()
for c in columns :
print(c[1])
conn.commit()
conn.close()
our-app.py
import app_database
table_name = input("Enter the table name = ")
app_database.column_names(table_name)
when I run our-app.py I don't get anything.
C:\Users\database-project>python our-app.py
Enter the table name = Employee
C:\Users\database-project>
Can anyone tell me how should I proceed?
I have been given a .db file, that has already been populated with both Tables and Data. However, no description of the content of the database has been made available.
Is there a way for me to retrieve individual lists listing the different tables, and their respective sets of columns using SQLite3 and python?
This code help you to show tables with keys , when you get tables and their keys you can get data.
import sqlite3
def readDb():
connection = sqlite3.connect('data.db')
connection.row_factory = sqlite3.Row
cursor = connection.cursor()
cursor.execute("SELECT name FROM sqlite_master WHERE type='table';")
rows = cursor.fetchall()
tabs=[]
for row in rows:
for r in row:
tabs.append(r)
d={}
for tab in tabs:
cursor.execute("SELECT * FROM "+tab+";")
rows = cursor.fetchone()
t=[]
for row in rows.keys():
t.append(row)
d[tab]=t
connection.commit()
return d
print(readDb())
I made new column with NULL values called 'id' in table. Now I want to add data to it from list. It holds about 130k elements.
I tried with insert, it returned error:
conn = create_connection(xml_db)
cursor = conn.cursor()
with conn:
cursor.execute("ALTER TABLE xml_table ADD COLUMN id integer")
for data in ssetId:
cursor.execute("INSERT INTO xml_table(id) VALUES (?)", (data,))
conn.commit()
I also tried with update:
conn = create_connection(xml_db)
cursor = conn.cursor()
with conn:
cursor.execute("ALTER TABLE xml_table ADD COLUMN id INTEGER")
for data in ssetId:
cursor.execute("UPDATE xml_table SET ('id' = ?)", (data,))
conn.commit()
What is incorrect here ?
EDIT for clarification.
The table was already existing, filled with data. I want to add column 'id' with custom values to it.
Heres an example similar to yours which may be useful.
import sqlite3
conn = sqlite3.connect("xml.db")
cursor = conn.cursor()
with conn:
# for testing purposes, remove this or else the table gets dropped whenever the file is loaded
cursor.execute("drop table if exists xml_table")
# create table with some other field
cursor.execute("create table if not exists xml_table (other_field integer not null)")
for other_data in range(5):
cursor.execute("INSERT INTO xml_table (other_field) VALUES (?)", (other_data,))
# add id field
cursor.execute("ALTER TABLE xml_table ADD COLUMN id integer")
# make sure the table exists
res = cursor.execute("SELECT name FROM sqlite_master WHERE type='table'")
print("Table Name: {}".format(res.fetchone()[0]))
# add data to the table
for data in range(5):
cursor.execute("UPDATE xml_table SET id = ? WHERE other_field = ?", (data, data))
# if you must insert an id, you must specify a other_field value as well, since other_field must be not null
cursor.execute("insert into xml_table (id, other_field) VALUES (? ,?)", (100, 105))
# make sure data exists
res = cursor.execute("SELECT id, other_field FROM xml_table")
for id_result in res:
print(id_result)
conn.commit()
conn.close()
As I stated in the comment below, since one of your rows has a NOT NULL constraint on it, no rows can exist in the table that have that column NULL. In the example above other_field is specified NOT NULL, therefore there can be no rows that have NULL values in the column other_field. Any deviation from this would be an IntegrityError.
Output:
Table Name: xml_table
(0, 0)
(1, 1)
(2, 2)
(3, 3)
(4, 4)
(100, 105)