RE: [sqlite] Difference between Transaction Journal and Checkpoint Journal
I'm going to make an assumption here, but it might make sense that the three are related to each other. Ie: A "journal" entry points to a entry in the "transaction journal," and "checkpoint journal." -- Journal: A mechanism which tracks changes made to data in the database between checkpoints. -Original Message- From: Rohit Nadhani [mailto:[EMAIL PROTECTED] Sent: Thursday, March 25, 2004 8:33 AM To: [EMAIL PROTECTED] Subject: [sqlite] Difference between Transaction Journal and Checkpoint Journal Hello, I was going thru the pager source code ( pager.c ). The comments include references to "Journal", "Transaction Journal", "Checkpoint Journal". What is the difference between the three? Am I missing something? Regards, Rohit - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
[sqlite] Difference between Transaction Journal and Checkpoint Journal
Hello, I was going thru the pager source code ( pager.c ). The comments include references to "Journal", "Transaction Journal", "Checkpoint Journal". What is the difference between the three? Am I missing something? Regards, Rohit - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
RE: [sqlite] mySQL to SQLite conversion question
1) adrsId INTEGER PRIMARY KEY If you insert a null value in "adrId," or not insert anything at all, then it will auto incremement. 2) You will not require NOT NULL, think about it. 3) I've found a really good e-book on advanced databasing, you can pick up a free copy here: http://216.197.101.104/emarketing/registration_form.cfm?pid=1=1=5 You'll have to give them some personal information, but I really think it's worth it. Regards, PeterP -Original Message- From: rich coco [mailto:[EMAIL PROTECTED] Sent: Wednesday, March 24, 2004 11:58 PM To: [EMAIL PROTECTED] Subject: [sqlite] mySQL to SQLite conversion question I see that the auto_increment keyword is not supported by SQLite: addressid bigint(20) unsigned NOT NULL auto_increment, . . . PRIMARY KEY (addressid) I understand that I have to move the 'unsigned' keyword (before 'bigint') but I do not know how to get the auto_increment semantic under SQLite. I found in the 'Datatypes in SQLite' manual page (in Section 2.0) the comment: "INTEGER PRIMARY KEY columns can be used to implement the equivalent of AUTOINCREMENT." Is the following the proper re-write to get the precise semantic I am seeking? addressid INTEGER PRIMARY KEY NOT NULL Can I then omit the subsequent "PRIMARY KEY (addressid)" line? Is "NOT NULL" no longer needed? Can someone recommend a good SQL book (I am not a DB guy)? There are so many out there and I'd like to purchase just one, so I need to get it right the first time. I found on-line manuals by DB engine providers - eg, http://www.mysql.com/doc/en/SQL_Syntax.html - but I do not know when I may be looking at specialized extentions (eg, mySQL's REGEXP and auto_increment keywords). I'd like to have my own reference. Tia, - rich -- rich coco [EMAIL PROTECTED] 781.736.1200 x165 Starbak Inc. 29 Sawyer Rd. Waltham, MA 02453 - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
[sqlite] mySQL to SQLite conversion question
I see that the auto_increment keyword is not supported by SQLite: addressid bigint(20) unsigned NOT NULL auto_increment, . . . PRIMARY KEY (addressid) I understand that I have to move the 'unsigned' keyword (before 'bigint') but I do not know how to get the auto_increment semantic under SQLite. I found in the 'Datatypes in SQLite' manual page (in Section 2.0) the comment: "INTEGER PRIMARY KEY columns can be used to implement the equivalent of AUTOINCREMENT." Is the following the proper re-write to get the precise semantic I am seeking? addressid INTEGER PRIMARY KEY NOT NULL Can I then omit the subsequent "PRIMARY KEY (addressid)" line? Is "NOT NULL" no longer needed? Can someone recommend a good SQL book (I am not a DB guy)? There are so many out there and I'd like to purchase just one, so I need to get it right the first time. I found on-line manuals by DB engine providers - eg, http://www.mysql.com/doc/en/SQL_Syntax.html - but I do not know when I may be looking at specialized extentions (eg, mySQL's REGEXP and auto_increment keywords). I'd like to have my own reference. Tia, - rich -- rich coco [EMAIL PROTECTED] 781.736.1200 x165 Starbak Inc. 29 Sawyer Rd. Waltham, MA 02453 - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
[sqlite] Text(3)
For the users using the Delphi components there is a property in TASQLiteTable and TASQLiteQuery to set or reset the 'typeless' property. Setting this property to 'false' (typed) means that all data-aware components of Delphi will react on the defined type (must be delphi compatible) and length, forcing correct data to be entered. Albert Drent sqlite.aducom.com - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: [sqlite] Text(3)
"Anabell Chan" <[EMAIL PROTECTED]>
24/03/2004 05:23 PM
Please respond to anabell
To: <[EMAIL PROTECTED]>
cc:
Subject:[sqlite] Text(3)
> Firstly, how do I define a string table field with constraints on its
size?
> For example Text(3), string of three characters. Secondly, how is it
> enforced during updates? Many thanks!
Sqlite will make you work a little to enforce contraints like this. If you
really want to, here's how:
CREATE TABLE foo (a); -- we want a to be at most three characters long
CREATE TRIGGER foo_a_insert_constraint BEFORE INSERT ON foo
BEGIN
SELECT RAISE(ABORT, "a is too long") WHERE length(NEW.a) > 3;
END;
CREATE TRIGGER foo_a_update_constraint BEFORE UPDATE OF a ON foo
BEGIN
SELECT RAISE(ABORT, "a is too long") WHERE length(NEW.a) > 3;
END;
sqlite> INSERT INTO foo VALUES("abcd");
SQL error: a is too long
sqlite> INSERT INTO foo VALUES("abc");
sqlite>
Adjust table and column names, and string length to suit. See
http://sqlite.org/lang.html#createtrigger for reference material. This
approach can be taken to check a wide variety of constraints. If you can
define a WHERE clause that can detect a problem, you can abort the
offending operation using a couple of triggers.
Does anyone have a more succinct version of the above?
Benjamin.
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