Posts Tagged ‘SQL’
How to export Oracle DB content to DBUnit XML flatfiles?
Case
From an Agile and TDD viewpoint, performing uni tests on DAO is a requirement. Sometimes, instead of using DBUnit datasets “out of the box”, the developper need test on actual data. In the same vein, when a bug appears on production, isolating and reproducing the issue is a smart way to investigate, and, along the way, fix it.
Therefore, how to export actual data from Oracle DB (or even MySQL, Sybase, DB2, etc.) to a DBUnit dataset as a flat XML file?
Here is a Runtime Test I wrote on this subject:
Fix
Spring
Edit the following Spring context file, setting the login, password, etc.
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"> <!-- don't forget to write this, otherwise the application will miss the driver class name, and therfore the test will fail--> <bean id="driverClassForName" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean"> <property name="targetClass" value="java.lang.Class"/> <property name="targetMethod" value="forName"/> <property name="arguments"> <list> <value>oracle.jdbc.driver.OracleDriver</value> </list> </property> </bean> <bean id="connexion" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean" depends-on="driverClassForName"> <property name="targetClass" value="java.sql.DriverManager"/> <property name="targetMethod" value="getConnection"/> <property name="arguments"> <list> <value>jdbc:oracle:thin:@host:1234:SCHEMA</value> <value>myLogin</value> <value>myPassword</value> </list> </property> </bean> <bean id="databaseConnection" class="org.dbunit.database.DatabaseConnection"> <constructor-arg ref="connexion"/> </bean> <bean id="queryDataSet" class="org.dbunit.database.QueryDataSet"> <constructor-arg ref="databaseConnection"/> </bean> </beans>
The bean driverClassForName
does not look to be used ; anyway, if Class.forName("oracle.jdbc.driver.OracleDriver")
is not called, then the test will raise an exception.
To ensure driverClassForName
is created before the bean connexion, I added a attribute depends-on="driverClassForName"
. The other beans will be created after connexion
, since Spring will deduce the needed order of creation via the explicit dependency tree.
Java
public class Oracle2DBUnitExtractor extends TestCase { private QueryDataSet queryDataSet; @Before public void setUp() throws Exception { final ApplicationContext applicationContext; applicationContext = new ClassPathXmlApplicationContext( "lalou/jonathan/Oracle2DBUnitExtractor-applicationContext.xml"); assertNotNull(applicationContext); queryDataSet = (QueryDataSet) applicationContext.getBean("queryDataSet"); } @Test public void testExportTablesInFile() throws DataSetException, IOException { // add all the needed tables ; take care to write them in the right order, so that you don't happen to fall on dependencies issues, such as ones related to foreign keys queryDataSet.addTable("MYTABLE"); queryDataSet.addTable("MYOTHERTABLE"); queryDataSet.addTable("YETANOTHERTABLE"); // Destination XML file into which data needs to be extracted FlatXmlDataSet.write(queryDataSet, new FileOutputStream("myProject/src/test/runtime/lalou/jonathan/output-dataset.xml")); } }
How to populate/insert/update a CLOB larger than 4000 or 32767 bytes?
A Short String
I have a table of which one field is a CLOB. Let’s say I have to insert one record with a short text. The following command is allowed:
INSERT INTO jonathan_table VALUES (1, 'hello world!');
A Bigger Text
Error ORA-01704
Now, my text is larger, let’s say 5000 characters. When I launch the same query, I get the following error:
ORA-01704: string literal too long
Indeed, Oracle/SQL*Plus have a limit on CLOB inserts: 4000 bytes.
Workaround
To pass through the limit on canonical SQL, you’ll have to use a PL/SQL procedure. The following command will be successful for any text larger than 4000 bytes, but shorter than 32767:
DECLARE bigtext1 VARCHAR2 (32767); BEGIN bigtext1 := lpad('X', 32000, 'X') INSERT INTO jonathan_table VALUES (1, bigtext1); END;
An Even Bigger Text
Errors ORA-06550 and PLS-00103
You guess it: beyond this limit of 32 KB, an error occurs. So the following script:
DECLARE bigtext1 VARCHAR2 (42000); BEGIN bigtext1 := lpad('X', 42000, 'X') INSERT INTO jonathan_table VALUES (1, bigtext1); END;
raises such an error:
Error at line 1 ORA-06550: line 5, column 4: PLS-00103: Encountered the symbol "INSERT" when expecting one of the following: . ( * % & = - + ; < / > at in is mod remainder not rem <an exponent (**)> <> or != or ~= >= <= <> and or like like2 like4 likec between || multiset member submultiset The symbol ";" was substituted for "INSERT" to continue.
Fix this issue
I searched a lot to find an easy fix to go beyond the limit of 32KB. My point was that with Java for instance there is no limit of 32KB. In the same way, with TOAD I was able to update the record with many mega bytes of text, via the clipboard. After further search, I learnt that the 32KB barrier was a SQL*Plus limitation on actual strings, but the patterns insert into ... select ... from
were not affected.
Here is the idea:
- create a temporary table
- split the text into blocks shorter than 32KB
- insert the blocks into the temporary table
- perform a first insert with a null CLOB
- update the record using a
select
on the temporary table (yet you can insert the actual value since previous step)
Here is an example:
DROP TABLE tt_jonathan_table; CREATE GLOBAL TEMPORARY TABLE tt_jonathan_table ( ID NUMBER(10), pdlsuffix CLOB ) ON COMMIT PRESERVE ROWS; TRUNCATE TABLE tt_jonathan_table; DECLARE bigtext1 VARCHAR2 (32767); bigtext2 VARCHAR2 (32767); BEGIN bigtext1 := lpad('X', 32000, 'X') bigtext2 := lpad('Y', 32000, 'Y') INSERT INTO tt_jonathan_table VALUES (1, bigtext1); INSERT INTO tt_jonathan_table VALUES (2, bigtext2); INSERT INTO jonathan_table (id, myClobField) VALUES (jonathan_seq.NEXTVAL, NULL); UPDATE jonathan_table SET myClobField = (SELECT CONCAT (rls1.myClobField, rls2.myClobField) FROM tt_jonathan_table rls1, tt_jonathan_table rls2 WHERE rls1.ID = 1 AND rls2.ID = 2) WHERE myClobField is null; END; / TRUNCATE TABLE tt_jonathan_table;
How to Read a BLOB for a Human Being?
Case
I have had to access a BLOB and read its content. By principle, I dislike using binary objects, which do not suit easy tracing and auditing. Anyway, in my case, floats are stored in a BLOB, and I need read them in order to validate my current development.
You have many ways to read the content of the BLOB. I used two: SQL and Java
SQL
Start your TOAD for Oracle ; you can launch queries similar to this:
SELECT UTL_RAW.cast_to_binary_float (DBMS_LOB.submyrecord (myrecord.myrecordess, 4, 1 + (myrecordessnameid * 4) ) ) AS myrecordessvalue FROM mytable myrecord WHERE myrecordessid = 123456;
You can also run a stored procedure, similar to this:
DECLARE blobAsVariable BLOB; my_vr RAW (4); blobValue FLOAT; bytelen NUMBER := 4; v_index NUMBER := 5; jonathan RAW (4); loopLength INT; BEGIN SELECT myField INTO blobAsVariable FROM myTable WHERE tableid = (5646546846); DBMS_LOB.READ (blobAsVariable, bytelen, 1, jonathan); loopLength := UTL_RAW.cast_to_binary_integer (jonathan); FOR rec IN 1 .. loopLength LOOP DBMS_LOB.READ (blobAsVariable, bytelen, v_index, my_vr); blobValue := UTL_RAW.cast_to_binary_float (my_vr); v_index := v_index + 4; DBMS_OUTPUT.put_line (TO_CHAR (blobValue)); END LOOP; END;
Java
I am still not sure to be DBA expert. Indeed I am convinced I am more fluent in Java than in PL/SQL 😉
Create a Spring configuration file, let’s say BlobRuntimeTest-applicationContext.xml
:
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"> <!-- $Id: BlobRuntimeTest-applicationContext.xml $ --> <bean id="dataSource" destroy-method="close" class="org.apache.commons.dbcp.BasicDataSource"> <property name="driverClassName" value="oracle.jdbc.driver.OracleDriver"/> <property name="url" value="jdbc:oracle:thin:@myDBserver:1234:MY_SCHEMA"/> <property name="username" value="jonathan"/> <property name="password" value="lalou"/> <property name="initialSize" value="2"/> <property name="minIdle" value="2"/> </bean> <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate"> <property name="dataSource" ref="dataSource"/> </bean> </beans>
Now create a runtime test:
/** * User: Jonathan Lalou * Date: Aug 7, 2011 * Time: 5:22:33 PM * $Id: BlobRuntimeTest.java $ */ public class BlobRuntimeTest extends TestCase { private static final Logger LOGGER = Logger.getLogger(BlobRuntimeTest.class); private static final String TABLE = "jonathanTable"; private static final String PK_FIELD = "jonathanTablePK"; private static final String BLOB_FIELD = "myBlobField"; private static final int[] PK_VALUES = {123, 456, 789}; private ApplicationContext applicationContext; private JdbcTemplate jdbcTemplate; @Before public void setUp() throws Exception { applicationContext = new ClassPathXmlApplicationContext( "lalou/jonathan/the/cownboy/BlobRuntimeTest-applicationContext.xml"); assertNotNull(applicationContext); jdbcTemplate = (JdbcTemplate) applicationContext.getBean("jdbcTemplate"); assertNotNull(jdbcTemplate); } @After public void tearDown() throws Exception { } @Test public void testGetArray() throws Exception { for (int pk_value : PK_VALUES) { final Blob blob; final byte[] bytes; final float[] floats; blob = (Blob) jdbcTemplate.queryForObject("select " + BLOB_FIELD + " from " + TABLE + " where " + PK_FIELD + " = " + pk_value, Blob.class); assertNotNull(blob); bytes = blob.getBytes(1, (int) blob.length()); // process your blob: unzip, read, concat, add, etc.. // floats = .... LOGGER.info("Blob size: " + floats.length); LOGGER.info(ToStringBuilder.reflectionToString(floats)); } } }
SQL*Plus Does Not Update a Stored Procedure
Case
You have a stored procedure that you would like to update. The script is OK with TOAD, but raises an error when launched via SQL*Plus.
Fix
Add a slash (‘/’) or a dot (‘.’) at the end of file.
Cannot run this command because Java services are not enabled. A user with System Administrator (SA) role must reconfigure the system to enable Java.
Context
An object is marshallized and sent on TibcoRV 8.1. An instance of Mule ESB 2.2.1 listens to TibcoRV, reads the message, unmarshalls the object and builds an SQL insert query.
The query is very simple:
insert into myTable(dateColumn, stringColumn) values(...)
It is executed in a Jdbc connector declared on Mule configuration file:
<jdbc:connector name="jdbcConnector" dataSource-ref="mySybaseDB" pollingFrequency="1000"> <jdbc:query key="writeTest" value="INSERT INTO myTable(dateColumn, stringColumn) VALUES(#[map-payload:myJavaDate],#[map-payload:myJavaString])"/> </jdbc:connector>
The DB is Sybase. The first column is of type datetime
, the second one is varchar
. The values are retrieved from a java.util.Date
and a java.lang.String
.
Case
When the query is run, I get the error:
java.sql.SQLException: Cannot run this command because Java services are not enabled. A user with System Administrator (SA) role must reconfigure the system to enable Java.
(you may get a com.sybase.jdbc2.jdbc.SybSQLException
instead of java.sql.SQLException
)
Explanation – Fix
The error is related only to Sybase, and not to TibcoRV and Mule: by default, Sybase cannot manage Java Dates (java.util.Date
). You have to start explicitly the Java services. To perform that:
- login with an username owing the rights “
sa_role
“ - run the SQL query:
sp_configure 'enable java', 1
- the restart the Sybase server
Now it should work. A similar error may occur with JBoss.