I'm trying to create a database with SQLite3 but each time I run sqlite3 test.db it just takes me onto a new line and no database is created. I assumed I had to add a table to the database as well so I created one and once done it just says Error: near "sqlite3": syntax error. So creating a table to complete the database creation was not the issue. I have searched all over the web and each resource is telling me to do the same thing I have been doing that only results in an error. If this is the same syntax all other online resources are using successfully, why is it constantly failing to create a database for me?
Here is a screenshot of the exact attempt:
You seem to have the order/placement of commands mixed up. From the folder containing SQLite on your system, you should create a database via sqlite3 somedb.db:
C:\path\to\sqlite>sqlite3 test.db;
sqlite> <-- prompt lets you know that you have connected
Once you have connected to that database, you don't need to specify it again for operations intended against that database. So, I expect the following CREATE TABLE statement to work:
sqlite> CREATE TABLE test.testtbl (
...> col1 text,
...> col2 text,
...> col3 text);
How do you attach two sqlite db inside a shell script and script operations with their aliases?
for example: from the sqlite3 shell I can attach two different dbs, lets say db1 and db2, and then use:
insert into db2.table1(column1) select column1 from db1.table1;
to copy one column from a specific table on db1 to a specific table on db2.
but, how do I do that same inside a shell script?
To give multiple lines to the input of another program, you could redirect from a temporary file, or from a here document:
sqlite3 "" <<EndOfSqlite3Commands
ATTACH 'database1.db' AS db1;
ATTACH 'database2.db' AS db2;
INSERT INTO db2.table1(column1) SELECT column1 FROM db1.table1;
EndOfSqlite3Commands
I have a Sqlite database file that i modify it by dropping a huge database table that contains thousands of records but the file size remains as it before dropping the table. it seems that it disconnect pointers to data . any ideas how to drop table and make a deep deletion of it in the underlying sqlite file .??
To reclaim space, use the vacuum statement.
From a sqlite prompt
sqlite> VACUUM;
From a shell prompt.
$ sqlite3 filename 'VACUUM;'
I have created a database "MyDB.sqlite" using the command line sqlite3 MyDB.sqlite in a specific folder(my desktop) and then created a table "tbl11" using create table syntax. I am able to insert record and can check the inserted records.
But when I exit command (terminal in Mac) line and re enter I can't see my database and tables in that folder. I guess this database and table are temporary by default. I even check the .databases command to see the database, but I can only see two database main!
please help!
Be sure to finish off with COMMIT; :-)
For practice, work through the short working example at http://souptonuts.sourceforge.net/readme_sqlite_tutorial.html
Good luck.
When I was searching for a tool to create and update SQlite databases for use in an Android application I was recommended to use SQLite Database Browser. This has a windows GUI and is reasonably powerful, offering in particular a menu option to import data to a new table from a CSV file.
This has proved perfectly capable for initial creation of the database and I have been using the CSV Import option to update the database whenever I have new data to be added.
When there were only a few records to import this worked well, however as the volume of data has grown the process has become painfully slow. A data file of 11,000 records (800 kilobytes) takes about 10 minutes to import on my averagely slow laptop. Using SQLite Database Browser the whole process of deleting the old table, running the import command, then correcting the data types of the new table created by the import command takes the best part of 15 minutes.
How can the import be speeded up?
You could use the built-in csv import (using the sqlite3 command line utility):
create table test (id integer, value text);
.separator ","
.import no_yes.csv test
Importing 10,000 records took less than 1 second on my Laptop.
By googling I have found several people asking this question, however I have not found the answer set out in once place in simple terms that I could understand. So, I hope the following will help.
The command line utility sqlite3.exe offers a very simple solution. The reason why the "import CSV" option in SQLite Database Browser is so slow is that it executes and commits to the database a separate SQL 'insert' statement foreach line in the CSV file. However, sqlite3.exe includes an "import" command which will process the whole in one go. What's more this is done virtually instantaneously: my 11,000 records are imported in well under a second.
There is a slight drawback in that the import command does not deal with commas in the same way as other programs such as Excel. For example,
if cell A1 in Excel contains Joe Bloggs
and cell B1 contains 123 Main Street, Anytown
the row is exported into a CSV file as:
Joe Bloggs,"123 Main Street, Anytown"
However, if you tried to import this using sqlite3 into a 2-column table, sqlite3 would report an error because it would treat each of the commas as a field separator and so would try to import Joe Bloggs, "123 Main Street and Anytown" as 3 separate fields.
Because it is unusual for text fields (especially in Excel) to include tabs this problem can usually be avoided by using a file where the fields are delimited by tabs rather than by commas.
Since sqlite3.exe can execute any SQL statement and a number of additional commands (like 'import') it is very flexible. However, a routine job like my need to import a delimited data file into a database table can be automated by:
listing the SQL statements and sqlite3.exe commands in a small text file, and feeding this file into sqlite3.exe as a command line parameter
writing a short Windows (MS-DOS) batch file to run sqlite3.exe with the specified list of commands.
These are the steps I followed:
Download and unzip sqlite3.exe
Convert the raw data from comma separated values to tab separated values.
Create a script file listing commands to be executed by sqlite3.exe as follows:
drop table tblTableName;
create table tblTableName(_id INTEGER PRIMARY KEY, fldField1 TEXT, fldField2 NUMERIC, .... );
.mode tabs
.import SubfolderName/DataToBeImported.tsv tblTableName
(Note: SQL statements are followed by a semi-colon; sqlite3.exe commands are preceded by a full stop (period))
Create a .bat file as follows:
cd "c:\users\UserName\FolderWhereSqlite3DatabaseFileAndScriptFileAreStored"
sqlite3 DatabaseName < textimportscript.txt
Having set this up, all I need to do whenever I have new data to add is run the batch file and the data is imported in an instant.
If you are generating INSERT statements, enclose them in a single transaction as stated in the official SQLite FAQ:
BEGIN; -- or BEGIN TRANSACTION;
INSERT ...;
INSERT ...;
END; -- can be COMMIT TRANSACTION; also
Have you tried wrapping all of your updates into a transaction? I had a similar problem and doing that sped it up no end.
Assuming Android Device:
db.beginTransaction();
// YOUR CODE
db.setTransactionSuccessful();
db.endTransaction();
Try that :)
sqlite> PRAGMA journal_mode=WAL;
sqlite> PRAGMA synchronous = 0;
sqlite> PRAGMA journal_mode=MEMORY;
memory
sqlite> BEGIN IMMEDIATE;
.import --csv blah.csv <tablename>
sqlite> COMMIT;
This turns off sync() on write, and puts the WAL file in memory, so it's not "safe", but as long as you are doing this "offline" as it were, and were OK re-creating the DB if power went out, disk gets full, etc, then this will def. speed up the import.