I have a table that I created using
CREATE TABLE `digiid_callback` ( `nonce` BINARY(8) NOT NULL, `address` BINARY(20), `expire` TIMESTAMP NOT NULL, PRIMARY KEY (`nonce`) )
So it has 3 fields. 1 is a timestamp and the other 2 hold a small binary data filed.
I am new to working with the yii framework and was wondering what the proper way to create an ActiveRecord for this table would be.
Normally if I was trying to select data from a table like this I would use
SELECT * FROM tablename WHERE nonce=UNHEX(?) LIMIT 1;
the yii equivalent seems to be ObjectName::findOne(?); but I don't know how to add the UNHEX which is needed.
First create DB table, then generate ActiveRecord (AR) class for that table using gii tool and then learn AR tutorial.
Related
So my use case is i have to find the location of the primary key column so that i can write query like select * from my_table where ID <='00000536-37ee-471c-a8e0-3d233b8102f5'
So my table has a primary key which is varchar type and values of the column is GUID generated by an application.
Here is an example of primary key
000000bd-104e-4fd6-a791-c5422f29e1b5
0000016e-7e68-4453-b360-7ffd1627dc22
00000196-2dba-4532-8cba-1e853c466697
0000025a-cfae-41b4-b8e7-ef854d49e54a
00000260-8bdb-4b30-acdb-5a67efd4dbfe
00000366-552d-48a0-b8a1-20190ccd087c
000003f2-d6d8-4a51-96cc-407063bc568b
000003ff-3d16-4e88-9cf3-bcdf01c39a2b
00000487-1e6c-4d6d-a683-6f11d517962c
000004cc-6359-4a9a-aa2a-70a6b73a06b1
00000536-37ee-471c-a8e0-3d233b8102f5
Now i need to use this table in aws DMS which accepts only query like select * from table where column =,<=,>=
My use case is to find the exact location of the millions of GUID so that i can divide table into multiple query and select based on GUID .
For example if we have 100th GID is 00000536-37ee-471c-a8e0-3d233b8102f5 then i can write query like select * from my table where GUID <=100
The limitation is i can not add any new columns in the existing table because application impact is huge .
How can i do this ?
One Option that i thought but wanted to confirm is below
Create a temp table
Temp table will have auto generated sequence and ID column
Inset into temp table select only GUID from main table with order of GUID .
In this case the value will be stored on order and i an first select GUID based on 100th number and then i can pass that GUID and write my oroginal query
But i am not sure whether this will work on not
Can some one suggest on this or suggest some other option ?
So let me explain what i want .
I want DMS to read may main table in parallel and migrate .
So lets say one DMS task can read nd migrate from 1 to 100,another 100 to 200 another >200 like that .
Currently i can not do because we dont know the position of the primary key and write the query .
If you want to divide your table into chunks of equal sizes, I would take advantage of the hexadecimal nature of the GUIDs. It will be 256 instead of 100 chunks, but this might be acceptable.
CREATE TABLE t (pk VARCHAR2(36) PRIMARY KEY);
INSERT INTO t VALUES ('000000bd-104e-4fd6-a791-c5422f29e1b5');
The easiest option would be
SELECT * FROM t WHERE pk LIKE '%b5';
A bit more advanced:
SELECT pk, to_number(substr(pk, -2),'xx') FROM t;
If you have millions of rows, this is probably faster:
ALTER TABLE t ADD (mycol GENERATED ALWAYS AS (to_number(substr(pk, -2),'xx')));
CREATE INDEX i ON t(mycol);
SELECT * FROM t WHERE mycol=181;
Once your migration is done, you can undo the additional virtual column:
DROP INDEX i;
ALTER TABLE t DROP (mycol);
Im trying to create a form with a report on a table that has only primary keys.
I have a table:
create table WRITE
(
author varchar(5) references AUTHOR (authorcode) ,
book varchar(20) references BOOK (bookid),
primary key(author,book)
);
I'm using APEX Application Builder to create a form on a table with report;
But When I get to the "Select the columns to include in the form" , I have no options to select from because I only have unique primary keys in my table.
Which Apex version is it? I've tried it on apex.oracle.com which uses 19.1 and it doesn't have that problem.
Anyway, two options I can think of:
temporarily drop primary key constraint
then create report + form pages
after you're done, create the primary key constraint once again
create an interactive report (using the wizard)
then create a form, manually adding items
this isn't as easy as it looks like because you'll have to create all processes as well (initialization one, along with automatic row processing)
I presume that the first option is a lot simpler.
How to create unique id in cassandra column families( like auto-increment id in mysql database ) ?
For unique IDs in Cassandra, you'll want to use UUIDs, which are probabilistically (nearly) guaranteed to be unique. There are a few built-in functions in CQL to help with UUIDs.
You asked for simple query to create table with uuid, so there you are:
create:
CREATE TABLE event (uuid uuid, name varchar);
insert:
INSERT INTO event(uuid, name) values(uuid(), 'john');
select:
SELECT * FROM event LIMIT 1;
to select on name column you must add new index:
CREATE index idx_event_name ON event(name);
and now you can select with where:
SELECT * FROM event WHERE name = 'john';
If you really need integer autoincrement IDs I've written a simple python module that does that after going through stackoverflow and not seeing anything decent that does that specific function. If you don't care about the ID being an integer you're better off using something like UUID which is probably safer and more elegant.
link: https://github.com/qdatum/globalcounter
I'm trying to move the data from one table TABLE5 another one TABLE5_BKP.
CREATE TABLE TABLE5_BKP AS SELECT * FROM TABLE5;
The table created and the data moved. when I checked the constraints,
The primary key,foreign key etc are not generated but all other constraints like,
SYS_C2211111 Check "COLUMN1" IS NOT NULL
etc are created. What to do in this case? Need to create the primary key,foreign key etc separately? What about indexes and other parameters, which I was not able to check.
You can't implicitly create PK, FK, Indexes, etc. just using
CREATE TABLE tablename AS SELECT *...
You have to specify them after creating. Also I suggest you to use oracle tools, like exp/imp, data pump, etc. if you want to move the database structure from one database to another.
I am reading a tutorial about Yii framework. It uses a term that I don't know its meaning. it is "Active Record model" . It uses in database section tutorial.
Would you give me more explanation about this term ?
From the Yii's documentation:
Active Record (AR) is a popular Object-Relational Mapping (ORM) technique. Each AR class represents a database table (or view) whose attributes are represented as the AR class properties, and an AR instance represents a row in that table. Common CRUD operations are implemented as AR methods. As a result, we can access our data in a more object-oriented way.
For example, we can use the following code to insert a new row to the tbl_post table:
$post=new Post;
$post->title='sample post';
$post->content='post body content';
$post->save();
In the following we describe how to set up AR and use it to perform CRUD operations. We will show how to use AR to deal with database relationships in the next section. For simplicity, we use the following database table for our examples in this section. Note that if you are using MySQL database, you should replace AUTOINCREMENT with AUTO_INCREMENT in the following SQL.
CREATE TABLE tbl_post (
id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
title VARCHAR(128) NOT NULL,
content TEXT NOT NULL,
create_time INTEGER NOT NULL
);
There is more on here.