For a seemingly good reason, I need to alter something in a table that was created from a fixture while a test runs.
Of many things I tried, here's what I have right now. Before I even get to the ALTER query, first I want to make sure I have access to that database where the temporary tables sit.
public function testFailingUpdateValidation()
{
// i will run SQL against a connection, lets get it's exact name
// from one of it's tables; first get the instance of that table
// (the setup was blindly copied and edited from some docs)
$config = TableRegistry::getTableLocator()->exists('External/Products')
? []
: ['className' => 'External/Products'];
$psTable = TableRegistry::getTableLocator()
->get('External/Products', $config);
// get the connection name to work with from the table
$connectionName = $psTable->getConnection()->configName();
// get the connection instance to run the query
$db = \Cake\Datasource\ConnectionManager::get($connectionName);
// run the query
$statement = $db->query('SHOW TABLES;');
$statement->execute();
debug($statement->fetchAll());
}
The output is empty.
########## DEBUG ##########
[]
###########################
I'm expecting it to have at least a name of that table I got the connection name from. Once I have the working connection, I'd run an ALTER query on a specific column.
How do I do that? Please help
Thought I'd clarify what I'm up to, if that's needed
This is a part of an integrated code test. The methods involved are already tested individually. The code inside the method I'm testing takes a bunch of values from one database table and copies them to another, then it immediately validates whether values in the two tables match. I need to simulate a case when they don't.
The best I could come up with is to change the schema of the table column in order to have it store values with low precision, and cause my code test to fail when it tries to match (validate) the values.
The problem was I didn't load the fixture for the table I wanted to ALTER. I know it's kind of obvious, but I'm still confused because then why didn't SHOW TABLES return the other tables that did have their fixtures loaded? It showed me no tables so I thought it was not working at all, and didn't even get to loading that exact fixture. Once I did, it now shows me the table of that fixture, and the others.
Anyway, here's the working code. Hope it helps someone figuring this out.
// get the table instance
$psTable = TableRegistry::getTableLocator()->get('External/Products');
// get the table's corresponding connection name
$connectionName = $psTable->getConnection()->configName();
// get the underlying connection instance by it's name
$connection = \Cake\Datasource\ConnectionManager::get($connectionName);
// get schemas available within connection
$schemaCollection = $connection->getSchemaCollection();
// describe the table schema before ALTERating it
$schemaDescription = $schemaCollection->describe($psTable->getTable());
// make sure the price column is initially DECIMAL
$this->assertEquals('decimal', $schemaDescription->getColumnType('price'));
// keep the initial column data for future reference
$originalColumn = $schemaDescription->getColumn('price');
// ALTER the price column to be TINYINT(2), as opposed to DECIMAL
$sql = sprintf(
'ALTER TABLE %s '.
'CHANGE COLUMN price price TINYINT(2) UNSIGNED NOT NULL',
$psTable->getTable()
);
$statement = $connection->query($sql);
$statement->closeCursor();
// describe the table schema after ALTERations
$schemaDescription = $schemaCollection->describe($psTable->getTable());
// make sure the price column is now TINYINT(2)
$this->assertEquals('tinyinteger', $schemaDescription->getColumnType('price'));
Note: after this test was done, I had to restore the column back to its initial type using the data from $originalColumn above.
Related
I could need some help with a Anylogic Model.
Model (short): Manufacturing scenario with orders move in a individual route. The workplaces (WP) are dynamical created by simulation start. Their names, quantity and other parameters are stored in a database (excel Import). Also the orders are created according to an import. The Agent population "order" has a collection routing which contains the Workplaces it has to stop in the specific order.
Target: I want a moveTo block in main which finds the next destination of the agent order.
Problem and solution paths:
I set the destination Type to agent and in the Agent field I typed a function agent.getDestination(). This function is in order which returns the next entry of the collection WP destinationName = routing.get(i). With this I get a Datatype error (while run not compiling). I quess it's because the database does not save the entrys as WP Type but only String.
Is there a possiblity to create a collection with agents from an Excel?
After this I tried to use the same getDestination as String an so find via findFirst the WP matching the returned name and return it as WP. WP targetWP = findFirst(wps, w->w.name == destinationName);
Of corse wps (the population of Workplaces) couldn't be found.
How can I search the population?
Maybe with an Agentlink?
I think it is not that difficult but can't find an answer or a solution. As you can tell I'm a beginner... Hope the description is good an someone can help me or give me a hint :)
Thanks
Is there a possiblity to create a collection with agents from an Excel?
Not directly using the collection's properties and, as you've seen, you can't have database (DB) column types which are agent types.1
But this is relatively simple to do directly via Java code (and you can use the Insert Database Query wizard to construct the skeleton code for you).
After this I tried to use the same getDestination as String an so find via findFirst the WP matching the returned name and return it as WP
Yes, this is one approach. If your order details are in Excel/the database, they are presumably referring to workplaces via some String ID (which will be a parameter of the workplace agents you've created from a separate Excel worksheet/database table). You need to use the Java equals method to compare strings though, not == (which is for comparing numbers or whether two objects are the same object).
I want a moveTo block in main which finds the next destination of the agent order
So the general overall solution is
Create a population of Workplace agents (let's say called workplaces in Main) from the DB, each with a String parameter id or similar mapped from a DB column.
Create a population of Order agents (let's say called orders in Main) from the DB and then, in their on-startup action, set up their collection of workplace IDs (type ArrayList, element class String; let's say called workplaceIDsList) using data from another DB table.
Order probably also needs a working variable storing the next index in the list that it needs to go to (so let's say an int variable nextWorkplaceIndex which starts at 0).
Write a function in Main called getWorkplaceByID that has a single String argument id and returns a Workplace. This gets the workplace from the population that matches the ID; a one-line way similar to yours is findFirst(workplaces, w -> w.id.equals(id)).
The MoveTo block (which I presume is in Main) needs to move the Order to an agent defined by getWorkplaceByID(agent.workplaceIDsList.get(nextWorkplaceIndex++)). (The ++ bit increments the index after evaluating the expression so it is ready for the next workplace to go to.)
For populating the collection, you'd have two tables, something like the below (assuming using strings as IDs for workplaces and orders):
orders table: columns for parameters of your orders (including some String id column) other than the workplace-list. (Create one Order agent per row.)
order_workplaces table: columns order_id, sequence_num and workplace_id (so with multiple rows specifying the sequence of workplace IDs for an order ID).
In the On startup action of Order, set up the skeleton query code via the Insert Database Query wizard as below (where we want to loop through all rows for this order's ID and do something --- we'll change the skeleton code to add entries to the collection instead of just printing stuff via traceln like the skeleton code does).
Then we edit the skeleton code to look like the below. (Note we add an orderBy clause to the initial query so we ensure we get the rows in ascending sequence number order.)
List<Tuple> rows = selectFrom(order_workplaces)
.where(order_workplaces.order_id.eq(id))
.orderBy(order_workplaces.sequence_num.asc())
.list();
for (Tuple row : rows) {
workplaceIDsList.add(row.get(order_workplaces.workplace_id));
}
1 The AnyLogic database is a normal relational database --- HSQLDB in fact --- and databases only understand their own specific data types like VARCHAR, with AnyLogic and the libraries it uses translating these to Java types like String. In the user interface, AnyLogic makes it look like you set the column types as int, String, etc. but these are really the Java types that the columns' contents will ultimately be translated into.
AnyLogic does support columns which have option list types (and the special Code type column for columns containing executable Java code) but these are special cases using special logic under the covers to translate the column data (which is ultimately still a string of characters) into the appropriate option list instance or (for Code columns) into compiled-on-the-fly-and-then-executed Java).
Welcome to Stack Overflow :) To create a Population via Excel Import you have to create a method and call Code like this. You also need an empty Population.
int n = excelFile.getLastRowNum(YOUR_SHEET_NAME);
for(int i = FIRST_ROW; i <= n; i++){
String name = excelFile.getCellStringValue(YOUR_SHEET_NAME, i, 1);
double SEC_PARAMETER_TO_READ= excelFile.getCellNumericValue(YOUR_SHEET_NAME, i, 2);
WP workplace = add_wps(name, SEC_PARAMETER_TO_READ);
}
Now if you want to get a workplace by name, you have to create a method similar to your try.
Functionbody:
WP workplaceToFind = wps.findFirst(w -> w.name.equals(destinationName));
if(workplaceToFind != null){
//do what ever you want
}
To give a simplified example:
I have a database with one table: names, which has 1 million records each containing a common boy or girl's name, and more added every day.
I have an application server that takes as input an http request from parents using my website 'Name Chooser' . With each request, I need to pick up a name from the db and return it, and then NOT give that name to another parent. The server is concurrent so can handle a high volume of requests, and yet have to respect "unique name per request" and still be high available.
What are the major components and strategies for an architecture of this use case?
From what I understand, you have two operations: Adding a name and Choosing a name.
I have couple of questions:
Qustion 1: Do parents choose names only or do they also add names?
Question 2 If they add names, doest that mean that when a name is added it should also be marked as already chosen?
Assuming that you don't want to make all name selection requests to wait for one another (by locking of queueing them):
One solution to resolve concurrency in case of choosing a name only is to use Optimistic offline lock.
The most common implementation to this is to add a version field to your table and increment this version when you mark a name as chosen. You will need DB support for this, but most databases offer a mechanism for this. MongoDB adds a version field to the documents by default. For a RDBMS (like SQL) you have to add this field yourself.
You havent specified what technology you are using, so I will give an example using pseudo code for an SQL DB. For MongoDB you can check how the DB makes these checks for you.
NameRecord {
id,
name,
parentID,
version,
isChosen,
function chooseForParent(parentID) {
if(this.isChosen){
throw Error/Exception;
}
this.parentID = parentID
this.isChosen = true;
this.version++;
}
}
NameRecordRepository {
function getByName(name) { ... }
function save(record) {
var oldVersion = record.version - 1;
var query = "UPDATE records SET .....
WHERE id = {record.id} AND version = {oldVersion}";
var rowsCount = db.execute(query);
if(rowsCount == 0) {
throw ConcurrencyViolation
}
}
}
// somewhere else in an object or module or whatever...
function chooseName(parentID, name) {
var record = NameRecordRepository.getByName(name);
record.chooseForParent(parentID);
NameRecordRepository.save(record);
}
Before whis object is saved to the DB a version comparison must be performed. SQL provides a way to execute a query based on some condition and return the row count of affected rows. In our case we check if the version in the Database is the same as the old one before update. If it's not, that means that someone else has updated the record.
In this simple case you can even remove the version field and use the isChosen flag in your SQL query like this:
var query = "UPDATE records SET .....
WHERE id = {record.id} AND isChosend = false";
When adding a new name to the database you will need a Unique constrant that will solve concurrenty issues.
I have some images stored in the default cluster in my OrientDB database. I stored them by implementing the code given by the documentation in the case of the use of multiple ORecordByte (for large content): http://orientdb.com/docs/2.1/Binary-Data.html
So, I have two types of object in my default cluster. Binary datas and ODocument whose field 'data' lists to the different record of binary datas.
Some of the ODocument records' RID are used in some other classes. But, the other records are orphanized and I would like to be able to retrieve them.
My idea was to use
select from cluster:default where #rid not in (select myField from MyClass)
But the problem is that I retrieve the other binary datas and I just want the record with the field 'data'.
In addition, I prefer to have a prettier request because I don't think the "not in" clause is really something that should be encouraged. Is there something like a JOIN which return records that are not joined to anything?
Can you help me please?
To resolve my problem, I did like that. However, I don't know if it is the right way (the more optimized one) to do it:
I used the following SQL request:
SELECT rid FROM (FIND REFERENCES (SELECT FROM CLUSTER:default)) WHERE referredBy = []
In Java, I execute it with the use of the couple OCommandSQL/OCommandRequest and I retrieve an OrientDynaElementIterable. I just iterate on this last one to retrieve an OrientVertex, contained in another OrientVertex, from where I retrieve the RID of the orpan.
Now, here is some code if it can help someone, assuming that you have an OrientGraphNoTx or an OrientGraph for the 'graph' variable :)
String cmd = "SELECT rid FROM (FIND REFERENCES (SELECT FROM CLUSTER:default)) WHERE referredBy = []";
List<String> orphanedRid = new ArrayList<String>();
OCommandRequest request = graph.command(new OCommandSQL(cmd));
OrientDynaElementIterable objects = request.execute();
Iterator<Object> iterator = objects.iterator();
while (iterator.hasNext()) {
OrientVertex obj = (OrientVertex) iterator.next();
OrientVertex orphan = obj.getProperty("rid");
orphanedRid.add(orphan.getIdentity().toString());
}
I am creating a small database for 'trial', per se. I have tried a few setting outs ([{key: value}, {key: value}]. But, I need a solution that can be called by an ID (12345), a name (Rob Alsod), an area (A4 (Like an apartment building)), or a job (Manager, Administrator, etc). So, something like a dictionary (which can only be called by one key) will not work. I tried making a 'Person' class, but I need a way to easily keep track of the classes, and also to assign them easily. For example,
for whatever in whatever:
what = Person(name = 'Rob Alsod', id = 12345, job = 'Admin', area = 'A1') # What can I make this iterate with? (Badly formed question)
My point is, as it loops through, I cannot assign it to the same thing again and again.
Could someone try to make sense of what I am saying, and suggest a way to format my database?
You could easily use SQLAlchemy with SQLite. SQL queries are only a few lines of code away:
from sqlalchemy import *
db = create_engine('sqlite:///people.db')
metadata = MetaData()
user = Table('people', metadata,
Column('ID', Integer, primary_key = True),
Column('name', String(16), nullable = False),
Column('area', String(16)),
Column('job', String(60))
)
After that it is easy connection = db.connect(); result = connection.execute("select ID from people")
On Linux, pip and apt-get make the install a breeze as well.
HTH, Phil
If you want small database for storing any objects identified by key you can use shelve module:
http://docs.python.org/3.2/library/shelve.html
I have in my DB (Sql server 2008) a id column with auto numeric set on.
I'm using EF and linq2entities
In some specific scenario I would like to be able to set a custom Id number (obviously I'm totally sure this value is not repeated), for example I would use it to "fill" missing Id numbers caused by deletions. I want to keep the auto increment prop in database, the problem is that when I do the linq sentence, the database assign the next Id number, not the one that I like.
Maybe it's a little weird but is it possible to do using linq2entities ?
Thanks in advance!
I believe Its not possible unless there is some way to turn off "SET Identity_Insert TableName ON" within Entity Framework.
Basically in SQL Server when you sent Identity on a field it cannot be populated manually unless you run the following statement
SET Identity_Insert TableName ON
After running this statement you will be able to populate Identity Fields manually.
The only other options I can think of is to remove the Identity attribute from the column and create your own incrementer for the field in the Entity Framework using a partial Class
Something like this
public partial class EntityClassName : global::System.Data.Objects.DataClasses.EntityObject, IEntity
{
partial void InitializeFields();
Int64 IEntity.IdentityColumn
{
get { return IdentityColumn; }
set { //some code for an incrementer
//and the ability to set manually
//if value provide is not null
}
}
}
I don't like to say flat-out that it's impossible, but this is pretty inside baseball for L2E. But it's a pretty simple INSERT trigger. You'll get the inserted row via INSERTED (Google will explain), and then you update that row with whatever crazy logic you want.
I think you can bang your head against L2E for hours trying to figure it out, or do it inside of twenty minutes with a trigger.