DDevelopment & Design

Insert into .. select… na oraclu gubi dane.

  • byradek
  • January 28, 2011
  • 1 minute read

Problem dotyczy serwra w wersji Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 – 64bi i pobrania danych z serwera zdalnego w wersji Oracle9i Enterprise Edition Release 9.2.0.8.0 – 64bit Production.

Na serwerze zdalnym mamy tabelę z danymi do zaczytania.

Dla ustalenia uwagi niech nazywa się tab_1 i będzie utworzona poleceniem:

CREATE TABLE tab_1
(ID NUMBER,
param_id NUMBER,
param_value VARCHAR2(4000));

Na systemie do którego chcę pobrać z niej dane tworzę perspektywę:

create or replace view v_tab1 as select * from tab_1 @db_link;

Po wykonaniu polecenia select * from v_tab1; widzimy wszystkie dane.

Tworzymy teraz w systemie docelowym tabelę tymczasową tmp_data:

CREATE GLOBAL temporary TABLE tmp_data
(ID NUMBER,
param_id NUMBER,
param_value VARCHAR2(4000))  ON COMMIT PRESERVE ROWS;

i próbujemy wykonać polecenie

insert into tmp_data select  id,param_id,  param_value from v_tab1 where id BETWEEN :1 and :2;

i od razu sprawdzamy wynik

select * from tmp_data ;

I niestety w ostatniej kolumnie zamiast spodziewanych danych są same nulle.

Cofam transakcję:

Rollback;

Zachowanie dziwne, ale jakoś trzeba sobie poradzić i te dane pobrać.

Robię prawie to samo, ale pobierając dane wykonuję konkatenację ostatniej kolumny z pustym stringiem (czyli nullem).

insert into tmp_data select id,param_id, '' || param_value as param_value  from v_tab1 where id BETWEEN :1 and :2;
select * from tmp_data ;
rollback;

Tym razem dane w tabelce tymczasowej są prawidłowe.

Podobny efekt zaobserwowałem z inną tablą, gdzie ostatnia kolumna była typu number

W rzeczywistym systemie na którym zaobserwowałem problem.

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DDevelopment & Design

Spock, Java and Maven

Few months ago I've came across Groovy - powerful language for JVM platform which combines the power of Java with abilities typical for scripting languages (dynamic typing, metaprogramming).

Together with Groovy I've discovered spock framework (https://code.google.com/p/spock/) - specification framework for Groovy (of course you can test Java classes too!). But spock is not only test/specification framework - it also contains powerful mocking tools.

Even though spock is dedicated for Groovy there is no problem with using it for Java classes tests. In this post I'm going to describe how to configure Maven project to build and run spock specifications together with traditional JUnit tests.


Firstly, we need to prepare pom.xml and add necessary dependencies and plugins.

Two obligatory libraries are:
<dependency>
    <groupid>org.spockframework</groupId>
    <artifactid>spock-core</artifactId>
    <version>0.7-groovy-2.0</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupid>org.codehaus.groovy</groupId>
    <artifactid>groovy-all</artifactId>
    <version>${groovy.version}</version>
    <scope>test</scope>
</dependency>
Where groovy.version is property defined in pom.xml for more convenient use and easy version change, just like this: 
<properties>
    <gmaven-plugin.version>1.4</gmaven-plugin.version>
    <groovy.version>2.1.5</groovy.version>
</properties>

I've added property for gmaven-plugin version for the same reason ;)

Besides these two dependencies, we can use few additional ones providing extra functionality:
  • cglib - for class mocking
  • objenesis - enables mocking classes without default constructor
To add them to the project put these lines in <dependencies> section of pom.xml:
<dependency>
    <groupid>cglib</groupId>
    <artifactid>cglib-nodep</artifactId>
    <version>3.0</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupid>org.objenesis</groupId>
    <artifactid>objenesis</artifactId>
    <version>1.3</version>
    <scope>test</scope>
</dependency>

And that's all for dependencies section. Now we will focus on plugins necessary to compile Groovy classes. We need to add gmaven-plugin with gmaven-runtime-2.0 dependency in plugins section:
<plugin>
    <groupid>org.codehaus.gmaven</groupId>
    <artifactid>gmaven-plugin</artifactId>
    <version>${gmaven-plugin.version}</version>
    <configuration>
        <providerselection>2.0</providerSelection>
    </configuration>
    <executions>
        <execution>
            <goals>
                <goal>compile</goal>
                <goal>testCompile</goal>
            </goals>
        </execution>
    </executions>
    <dependencies>
        <dependency>
            <groupid>org.codehaus.gmaven.runtime</groupId>
            <artifactid>gmaven-runtime-2.0</artifactId>
            <version>${gmaven-plugin.version}</version>
            <exclusions>
                <exclusion>
                    <groupid>org.codehaus.groovy</groupId>
                    <artifactid>groovy-all</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupid>org.codehaus.groovy</groupId>
            <artifactid>groovy-all</artifactId>
            <version>${groovy.version}</version>
        </dependency>
    </dependencies>
</plugin>

With these configuration we can use spock and write our first specifications. But there is one issue: default settings for maven-surefire plugin demand that test classes must end with "..Test" postfix, which is ok when we want to use such naming scheme for our spock tests. But if we want to name them like CommentSpec.groovy or whatever with "..Spec" ending (what in my opinion is much more readable) we need to make little change in surefire plugin configuration:
<plugin>
    <groupid>org.apache.maven.plugins</groupId>
    <artifactid>maven-surefire-plugin</artifactId>
    <version>2.15</version>
    <configuration>
        <includes>
            <include>**/*Test.java</include>
            <include>**/*Spec.java</include>
        </includes>
    </configuration>
</plugin>

As you can see there is a little trick ;) We add include directive for standard Java JUnit test ending with "..Test" postfix, but there is also an entry for spock test ending with "..Spec". And there is a trick: we must write "**/*Spec.java", not "**/*Spec.groovy", otherwise Maven will not run spock tests (which is strange and I've spent some time to figure out why Maven can't run my specs).

Little update: instead of "*.java" postfix for both types of tests we can write "*.class" what is in my opinion more readable and clean:
<include>**/*Test.class</include>
<include>**/*Spec.class</include>
(thanks to Tomek Pęksa for pointing this out!)

With such configuration, we can write either traditional JUnit test and put them in src/test/java directory or groovy spock specifications and place them in src/test/groovy. And both will work together just fine :) In one of my next posts I'll write something about using spock and its mocking abilities in practice, so stay in tune.