What am I doing wrong here? It run's without error, it has created table, but rows are empty. Why?
import sqlite3
sqlite_file = (r"C:\Users\Dragan\PycharmProjects\MyProject\ArchLib2.db")
conn = sqlite3.connect(sqlite_file)
cursor = conn.cursor()
table_name = 'Archive'
sql = 'CREATE TABLE IF NOT EXISTS ' + table_name + '("first_name" varchar NOT NULL, "second_name" varchar NOT NULL)'
cursor.execute(sql)
sql = 'INSERT INTO ' + table_name + '(first_name,second_name) VALUES ("value1","value2");'
cursor.execute(sql)
cursor.close()
Ok so I found why it didn't INSERT data into table.
data in sql = string didnt have good formating ( this ' must be replaced with this "
second if you have string value like "value1" it has to have backslash on both sides like this "\value1\"
third and most important after insert execution line you have to add this line conn.commit()
Final code looks like this:
import sqlite3
sqlite_file = (r"C:\Users\Dragan\PycharmProjects\MyProject\ArchLib2.db")
conn = sqlite3.connect(sqlite_file)
cursor = conn.cursor()
table_name = 'Archive'
sql = "CREATE TABLE IF NOT EXISTS " + table_name + "(first_name varchar NOT NULL, datetime)"
cursor.execute(sql)
sql = "INSERT INTO " + table_name + "(first_name,datetime) VALUES (\"value1\",CURRENT_TIMESTAMP)"
cursor.execute(sql)
conn.commit()
cursor.close()
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 am using DataFrame to read data from each postgres table and using to_sql() method to insert data into the oracle. The problem I am facing is that It gets stuck after copying a few records to oracle. Jupyter Notebook gets busy but does nothing.
def duplicateData(conn, conn2, session):
query1 = "SELECT table_name FROM information_schema.tables WHERE table_schema = 'public'"
all_tables = session.execute(query1)
count = 0
for index,tables in enumerate(all_tables):
count += 1
# getting rid of comma and parathesis
for i, table in enumerate(tables):
print("\n"+table+" - NO: "+str(count)+"\n")
query2 = "SELECT column_name FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = '" + table + "'"
columns = session.execute(query2)
cols = []
for col in columns:
cols.append(col[0])
query3 = "SELECT * FROM " + table
df = pd.read_sql(query3, conn)
alias = (table[:30] + '') if len(table) > 30 else table
df.to_sql(alias, conn2, index=False, schema="PMS")
print("\nDONE\n")
I created one-to-many relationship table and according to the sqlite3 documentation I can't insert value into the child table if the referenced table column value in the parent table does not exist.
import sqlite3
class Database:
def __init__(self, database_name):
self.database_name = database_name
def create_table(self, table_name, *columns):
columns = ", ".join(columns)
conn = sqlite3.connect(self.database_name)
cursor = conn.cursor()
_SQL = f"CREATE TABLE IF NOT EXISTS {table_name}({columns})"
cursor.execute(_SQL)
conn.commit()
cursor.close()
conn.close()
def insert_values(self, table_name, values, *columns):
dynamic_values = ('?, ' * len(columns))[0:-2]
columns = ", ".join(columns)
conn = sqlite3.connect(self.database_name)
cursor = conn.cursor()
_SQL = f"INSERT INTO {table_name}({columns}) VALUES ({dynamic_values})"
cursor.execute(_SQL, values)
conn.commit()
cursor.close()
conn.close()
def view_values(self, table_name, *columns):
columns = ", ".join(columns)
conn = sqlite3.connect(self.database_name)
cursor = conn.cursor()
_SQL = f"SELECT {columns} FROM {table_name}"
cursor.execute(_SQL)
the_data = cursor.fetchall()
cursor.close()
conn.close()
return the_data
data = Database("games.db")
#
# data.create_table("supplier_groups", "group_id integer PRIMARY KEY", "group_name text NOT NULL")
#
data.insert_values("supplier_groups", ("Domestic", ), "group_name")
# data.create_table("suppliers ", "supplier_id INTEGER PRIMARY KEY",
# "supplier_name TEXT NOT NULL",
# "group_id INTEGER NOT NULL, "
# "FOREIGN KEY (group_id) REFERENCES supplier_groups (group_id)")
data.insert_values("suppliers", ('ABC Inc.', 9), "supplier_name", "group_id")
as you see on this line: data.insert_values("supplier_groups", ("Domestic", ), "group_name") - I'm inserting a value into supplier_groups table
and then right here: data.insert_values("suppliers", ('ABC Inc.', 9), "supplier_name", "group_id") - I'm inserting value into suppliers table with the group_id that does not exist in the group_suppliers table. Python executes it successfully and adds value to the database, however when attemping to execute this command in SQLITE browser I get this error:
Execution finished with errors. Result: FOREIGN KEY constraint failed which is what python should also have done instead of adding it into the database.
So, could anyone explain me what's going on here? Do I understand something in the wrong way? Help would be appreciated
From Section 2. Enabling Foreign Key Support in the sqlite doc:
Assuming the library is compiled with foreign key constraints enabled, it must still be enabled by the application at runtime, using the PRAGMA foreign_keys command. For example:
sqlite> PRAGMA foreign_keys = ON;
conn = pyodbc.connect("DRIVER={SQL Server};"
"SERVER="+server+";"
"UID="+username+";"
"PWD="+password,
autocommit=True)
cursor = conn.cursor()
database= "abcd"
sql_create = (
"DECLARE #sql AS NVARCHAR(MAX);"
"SET #sql = 'if not exists(select * from sys.databases where name = ' + QUOTENAME(?) + ')' + ' CREATE DATABASE ' + QUOTENAME(?);"
"EXEC sp_executesql #sql")
cursor.execute(sql_create,database,database)
Getting error msg like pyodbc.ProgrammingError: ('42S22', u"[42S22] [Microsoft][ODBC Driver 17 for SQL Server][SQL Server]Invalid column name 'abcd'. (207) (SQLExecDirectW)")"
Don't use QUOTENAME and concatenation for the WHERE clause parameter. Also, avoid using the legacy SQL Server ODBC driver that ships with Windows to access Azure SQL Database. Instead, download and use a newer ODBC driver. Below is an example with these changes.
conn = pyodbc.connect("DRIVER={ODBC Driver 17 for SQL Server};"
"SERVER="+server+";"
"UID="+username+";"
"PWD="+password,
autocommit=True)
cursor = conn.cursor()
database= "abcd"
sql_create = (
"DECLARE #sql AS NVARCHAR(MAX);"
"SET #sql = N'if not exists(select * from sys.databases where name = #DatabaseName)' + N' CREATE DATABASE ' + QUOTENAME(?) + N';';"
"EXEC sp_executesql #sql, N'#DatabaseName sysname', #DatabaseName = ?;")
cursor.execute(sql_create,database,database)
You could also declare a T-SQL variable for the database name and assign it to the parameter value so that you only need to pass a single parameter:
sql_create = (
"DECLARE #sql AS NVARCHAR(MAX);"
"DECLARE #DatabaseName sysname = ?;"
"SET #sql = N'if not exists(select * from sys.databases where name = #DatabaseName)' + N' CREATE DATABASE ' + QUOTENAME(#DatabaseName) + N';';"
"EXEC sp_executesql #sql, N'#DatabaseName sysname', #DatabaseName = #DatabaseName;")
cursor.execute(sql_create,database)
Why following code is giving syntax error "sqlite3.OperationalError: near "?": syntax error"
import sqlite3
connection = sqlite3.connect('data.db')
cursor = connection.cursor()
table = "device_store"
uuid = "bbebe39e-fe2e-4817-b022-a3ef13bd6283"
page = 1
POSTS_PER_PAGE = 10
query = "SELECT * FROM ? WHERE uuid=? LIMIT ? OFFSET ?"
result = cursor.execute(query, (table, uuid, POSTS_PER_PAGE, 0))
rows = result.fetchall()
connection.close()
print("==>> Printing rows <<==")
print(rows)
The error is caused by the placeholder in FROM ?, not the others. Table names can't be passed as parameters, they have to be hardcoded in the statement.