For SQL Lite why doesn't this table command work? - sqlite

Question

So I made a table using this command
.open C:/Users/Fries/Desktop/Test.db
I closed SQL lite and populated the db with the data below using notepad
CREATE TABLE Persons (
PersonID int,
LastName varchar(255),
FirstName varchar(255),
Address varchar(255),
City varchar(255)
);
When I open the db and type .tables there is an error for some reason

Answer 1

The commands do work when used properly.
In short what you have done, is
Create and save a database that has no tables.
Open that file with Notepad (despite warnings that you may have received)
Entered some data and saved the file.
Thus deleting eveything in the file that SQLite knows about so when you open it SQLite tells you that it's not a database e.g. the first 16 bytes must be SQLite format 3\000 (see below when the database file is opened in notepad).
Open the file from within the SQLITE3 program which has then told you it's not a database.
i.e. The file that you open is the actual database not something that you have typed into notepad.
The data, which will be in columns of a table or tables. Has to be entered via SQLITE3 commands (including SQL). The CREATE TABLE... is one such SQL command (yours is valid and has been used below as it is).
What you should be doing is starting SQLIT3 (typing sqlite3 if it's path has been added to the PATH environment variable), and then entering commands such as CREATE TABLE ......
E.G.
When you first start sqlite3 from a command prompt you will get :-
C:\Users\Mike>sqlite3
SQLite version 3.22.0 2018-01-22 18:45:57
Enter ".help" for usage hints.
Connected to a transient in-memory database.
Use ".open FILENAME" to reopen on a persistent database.
A database is opened as such but it is an in memory database and would be lost if you quit.
You can create an on disk database by opening it (even if it doesn't exist) using .open and then entering commands. Alternately you can enter commands and then then use the .save command afterwards to save the in-memory database to disk.
So after the above you could do :-
sqlite> .open Test.db
sqlite> CREATE TABLE Persons ( PersonID int, LastName varchar(255), FirstName varchar(255), Address varchar(255), City varchar(255) );
sqlite> SELECT * FROM Sqlite_master;
table|Persons|Persons|3|CREATE TABLE Persons ( PersonID int, LastName varchar(255), FirstName varchar(255), Address varchar(255), City varchar(255) )
sqlite> .quit
This creates the file Test.db (which didn't exists, otherwise it would open it)
Then creates the Persons table.
And then extracts the rows in the system table named sqlite_master (lists items including tables).
Finally it quites from SQLITE3.
Perhaps you could then do
:-
C:\Users\Mike>sqlite3 SQLite version 3.22.0 2018-01-22 18:45:57 Enter ".help" for usage hints. Connected to a transient in-memory database. Use ".open FILENAME" to reopen on a persistent database.
sqlite> .open Test.db
sqlite> .tables Persons
sqlite> INSERT INTO Persons VALUES (1,'Smith','Fred','Somewhere','London');
sqlite> select * FROM persons; 1|Smith|Fred|Somewhere|London sqlite> .quit
Starts SQLITE3
Opens the now existing Test.db file.
Lists the tables.
inserts a row
dispslays the rows in the Persons table (i.e. the row just added)
Finally quits SQLITE3
Opening the file Test.db in notepad :-
SQLite format 3 # .°
e e ‚tablePersonsPersonsCREATE TABLE Persons ( PersonID int, LastName varchar(255), FirstName varchar(255), Address varchar(255), City varchar(255) )
You may see some familiar data (e.g. the SQL used to create the table is stored in the sqlite_master table in the column named SQL and will be visible as is)
Other data will not be shown in a usefule/usable format.
i.e. You will find it between hard and impossible to enter the correct data to create a valid SQLite3 database file in notepad.