I have a data source for SQLServer created in Weblogic with username 'sa'.
In code I am using following to get user name.
Context ctx = new InitialContext(prop);
Object obj = ctx.lookup("sqlserver1");
System.out.println("Data Source Found….");
DataSource ds = (DataSource) obj;
Connection conn = ds.getConnection();
DatabaseMetaData mtdt = conn.getMetaData();
// Get UserName
System.out.println("User name: " + mtdt.getUserName());
But above code always returns 'dbo' as the username. I expected the username to be 'sa'. If the DB is Oracle it works fine. Is there a generic way for me to get user name for all different types of database.
The correct method should be DatabaseMetaData.getUserName(), but as you demonstrate not all databases implement that correctly. Another way would be to use the JDBC function escape USER() eg (eg SELECT {fn USER()} FROM DUAL), but not all drivers implement all JDBC escapes, and it could just be that this returns the same as the DatabaseMetaData. You could also try the SQL standard defined CURRENT_USER (or USER) in a query, but there you have two problems: 1) some databases require you to select from a table (eg DUAL in Oracle, some don't) and 2) not all databases implement all parts of the SQL standards, so the CURRENT_USER or USER context variable might be absent.
But as you have the DataSource object, you could try to get the user property from the datasource (it is defined in table 9.1 of the JDBC 4.1 specification, although the property names described there are not all required).
So for example:
Method getter = new PropertyDescriptor("user", ds.getClass()).getReadMethod();
String value = (String) getter.invoke(ds);
This assume that 1) the DataSource ds has a getUser() and 2) that it is actually set (for example with SQL Server integrated security the datasource doesn't need to know about a user).
FWIW, Java 1.7 provides the Connection.getSchema() method. I don't know how widely 1.7 has been adopted at this point however, so this might just be something to keep in mind for future reference.
Related
I have a table user in a MySQL database, and I created a class User for my project. I would like to get the record directly in a User object as in Hibernate, without using Hibernate:
User u = (User) session.get(User.class, id);
I use a JDBC driver.
Is there any way to get a result set as Object like:
Statement stmt = db.createStatement();
User u = stmt.executeQuery("SELECT * FROM user",User.class);
I am a lazy programmer, I wouldn't create a list, create a loop to iterate it and set all variables.
I've solved.
#Kayaman I've found ORMlite library.
String databaseUrl = "...";
ConnectionSource cs = new JdbcConnectionSource(databaseUrl);
Dao<User,Integer> userDAO = DaoManager.createDao(cs, User.class);
User u = userDAO.queryForId(1);
System.out.println(u.getName());
For http://ormlite.com/javadoc/ormlite-core/doc-files/ormlite_1.html#Getting-Started
Short answer: No.
What you are asking for is called an ORM. JDBC is not an ORM. Hibernate is an ORM for Java, which uses JDBC to actually connect to and interact with the database server. EclipseLink is another Java ORM (it is the one included with glassfish).
At the first stage i'm managing my app via JDBC, so i'm the resposible to build and validate all the SQL. But i was wondering if JPA could give me a hand on these tasks.
So, at this moment i've already have a DbaUser model, which was generated from the DBA_USERS table on the OracleDB, and i can actually list all of them.
However, i'm trying to manage to create or update more, but whenever i try to create using
em.createQuery("CREATE USER C##ANTONIO IDENTIFIED BY Antionio123").executeUpdate();
An syntax exception is launched: The query does not start with a valid identifier, has to be either SELECT, UPDATE or DELETE FROM.
Could you guys enlighten me a bit more or pointing me to some proper tutorials? I've been googling but nothing concrete apprears on Oracle DBs system tables.
Update1 (Thanks to #JB Nizet)
After replacing the execution of the query from JPQL to Native SQL, i've got an error such as:
Query: DataModifyQuery(sql="CREATE USER C? IDENTIFIED BY ANTONIO123").
I've replaced the hashtags with a scape character "...C##..." with "...C\#\#..." but the issue earns a different flavour:
Query: DataModifyQuery(sql="CREATE USER C\? IDENTIFIED BY ANTONIO123")
... and i really need to send the "##" to the Oracle DB. How can i force these special characters?
Update 2
So...after googling a bit more, i've found out positional parameters, and i've also discovered that we cannot have named paramteres on JPA native queries. After this, i've tried:
em.createNativeQuery("CREATE USER ?1 IDENTIFIED BY ANTONIO123").setParameter(1, "C##ANTONIO").executeUpdate();
Which triggers: ORA-01935: missing user or role name
alongside with
Error Code: 1935
Call: CREATE USER ? IDENTIFIED BY ANTONIO123
Which tells me that this binding doesn't work. Is there another way to do it?
Kind regards and thanks in advance,
Sammy
createQuery() expects a JPQL query. What you passed is not JPQL. It's SQL.
Use createNativeQuery() to execute SQL.
To create a common user (prefixed with C##) you (i.e. your JPA connection pool user) need a specific priviledges.
CREATE ROLE and
SET CONTAINER
Those are not a typical privileges granted to a JPA connection, so I'm guessing you will fail with the creation of a new common user.
Additionally you need to be connected to the root container.
The further example are plain JDBC called from Groovy, it should be easy possible to pass it to JPA if you get the DB connection.
def stmt = con.prepareStatement("SELECT SYS_CONTEXT('USERENV', 'CON_NAME') CON_NAME FROM dual")
def rs = stmt.executeQuery()
while(rs.next())
{
println "container name= ${rs.getString('CON_NAME')}"
}
gives
container name= CDB$ROOT
Note that if you are connected to a local DB, you get an error while trying to create a user prefixed with C##
ORA-65094: invalid local user or role name
If both conditions are fulfilled, it is possible to create / drop the common user:
String cu = "create user \"C##TEST\" identified by password123 profile \"DEFAULT\" account unlock"
con.createStatement().execute(cu)
resp.
cu = "drop user \"C##TEST\""
con.createStatement().execute(cu)
Finally should be stated, that this exercise was done for the aim of completeness only. I do not see a real use case for a JPA pool connection to be granted such privileges and connecting the root container. The database maintenance is typically done not using JPA.
Another option would be to create a stored procedure in the database and then invoke stored procedure from JPA, thus you do not need to bother about caveats and syntax.
E.g.assume that JPA provider is EclipseLink
Database stored procedure
CREATE OR REPLACE PROCEDURE p_user_creation (p_username IN VARCHAR2,
p_password IN VARCHAR2,
p_return OUT NUMBER)
IS
v_syntax VARCHAR2 (256);
BEGIN
IF (p_username IS NOT NULL)
THEN
v_syntax :=
'CREATE USER '''
|| p_username
|| ''' IDENTIFIED BY '''
|| p_password
|| '''';
EXECUTE IMMEDIATE v_syntax;
p_return := 0;
END IF;
EXCEPTION
WHEN OTHERS
THEN
raise_application_error (-20002, 'An error has occurred!');
END;
Java code snippet to invoke stored procedure
try {
Integer returnValue = null;
StoredProcedureQuery storedProcedureQuery =
getEntityManager().createStoredProcedureQuery("p_user_creation");
storedProcedureQuery.registerStoredProcedureParameter("p_username", String.class, ParameterMode.IN);
storedProcedureQuery.registerStoredProcedureParameter("p_password", String.class, ParameterMode.IN);
storedProcedureQuery.registerStoredProcedureParameter("p_return", Integer.class, ParameterMode.OUT);
storedProcedureQuery.setParameter("p_username", "SCOTT");
storedProcedureQuery.setParameter("p_password", "tiger");
storedProcedureQuery.execute();
returnValue = (Integer) storedProcedureQuery.getOutputParameterValue("p_return");
} catch (Exception e) {
log.error("Error " + e.getMessage());
}
So I have been playing around with querying databases using the standard
Statement s = connection.createStatement();
ResultSet rs = s.executQuery(queryString);
ResultSetMetadata rsmd = rs.getMetaData();
while(rs.next)){
String code = "";
String value = "";
for(int i = 1; i <= rsmd.getColumnCount(); i++){
Object obj = rs.getObject(i);
if(i == 1){
code = obj.toString():
}
else{
label = obj.toString();
}
}
//Store code and labels in map
}
...go on to close statement and move on.
I am trying to select two columns from a table in each instance.
For the most part this works well. When working with MySql & Microsoft Sql databases I get a result set full of data in the table. However when I try to do this with an Oracle database I get an empty result set.
I have tested my query string in the SQL Developer application and it works fine, returns my data. But the result set doesnt contain anything. The resultSet metadata says that it has two columns though. Is there anything I need to do when interacting with an Oracle Database that is different from the other two? Thanks.
If your query works when you run it against the Oracle database, and you know the code works since you've run it against MySQL, then some other things to try are:
1.) Make sure your JDBC connection URL is correct. Are you sure you are connecting to the database that you intend to? (i.e. - the one that would return the rows you expect?)
2.) Take into account credentials. Make sure you are using the same credentials through JDBC that you are when connecting to Oracle directly.
3.) Make sure both connections are being made from the same machine and with the same environment. Oracle drivers rely on environment variables to find a file (I believe it is called tnsnames.ora, or something like that) that contains the alias & connection info. Getting different versions of that file could point you to different Oracle instances.
4.) Try manually specifying your schema name in the query. So instead of select * from my_table use select * from my_schema.my_table. Sometimes Oracle clients will configure their sessions to have default schemas set up in their preferences.
5.) If your are attempting to select data that you've inserted with your Oracle client, make sure you've committed the transaction in your Oracle client so that the data is visible to other sessions.
One last debugging tool to use is to try connecting via the Squirrel DB client. Squirrel is a 100% pure java SQL client that connects to any DB using JDBC. It would be a good test to make sure your JDBC Driver, Connection URL, etc. are all valid.
The database table has records but the JDBC client can't retrieve the records. Means the JDBC client doesn't have the select privileges. Please run the below query on command line:
grant all on emp to hr;
I have a a project name drop-down list, and based on the selected value a schema drop-down list is generated.
After the schema list is generated, there is a 'choose file' option where a script name is chosen which is to be run on multiple schemas.
Both the project list values and the schema list values are stored in the database. There is another table in the database where the schema credentials are stored.
I want to know that how create connections on those multiple schemas, and how to run a script in multiple schemas selected from that schema drop-down list.
I have executed the code in one schema using iBatis framework using scriptrunner method.
Table 1: ProjectName
PROJECT_PK,
PROJECT_CODE,
PROJECT_NAME
Table2: ComponentName
COMPONENT_PK,
COMPONENT_CODE,
COMPONENT_NAME,
PROJECT_PK
Table 3: SchemaName (This table contains the credentials of Other Schemas)
SCHEMA_PK,
SCHEMA_NAME,
PASSWORD,
ORACLE_SID,
HOST_NAME,
PORT_ID
Table 4: PROJECT_DETAIL
PROJECT_DETAIL_PK,
COMPONENT_PK,
SCHEMA_PK
Table5: COMPONENT_DETAILS
COMPONENT_DETAILS_PK,
PROJECT_PK,
SCHEMA_PK
I am attaching the scenario image.
I propose you create a 'super-schema' with the appropiate grants on every other schema, and create your JDBC connection for this 'super-schema'. This will make you need some tampering with the sql script - you will need to write it with some marker to easily substitute the schema, something like
ALTER TABLE ${SCHEMA_MARKER}.INVOICES ADD CLIENT_ADRRESS Varchar2(35);
And your java code would substitute it for the schema you are targeting. With some imagination you can extend this idea to execute bulk DDL scripts on all your schemas.
By the way, I understand by your question that you have many schemas with the same structure. I was forced once to work with such a legacy structure, and so I know there is a lot of momentum in corporate structures; nonetheless I must recommend you to redesign such system. Think for example in creating materialized views on your super-schema, replicating your schema structure but with a new field in every table primary key (this new field would fill the gap that made whomever did it separe the data in many schemas for starters).
This will surely make your query cache suffer a lot less, and will make easier the development of any new software that needs to work with that 'distributed' data.
In Oracle, a schema is basically a user. So to create a table FOO in the schema SX, you just login as user SX and execute create table FOO (...) (without specifying a schema). The user == schema convention in Oracle will make sure this works.
To login as user SX, get hold of your DataSource and use getConnection(String username, String password) instead of the default getConnection()
Alternative ways are to add placeholders in your script that you process to generate valid SQL first. See the answer by Jorge_B for an example.
Lastly, you can change the default schema using ALTER SESSION (see Default Schema in Oracle Connection URL). The problem with this approach is that you must restore the schema before closing the connection when using a web container with a DataSource - in this scenario, connections are never really closed, so the next piece of code asking for a connection will get one with an unexpected default schema -> hard to find errors.
Here is the DAO class to create multiple schema connection on the same database at run time.
We need to enter the schema names at run time through and call that in some servlet.
The schema details i.e username, password,host Id,port Id and SID are to be stored in the database tables though which the connections will be created.
The created connections are stored here in the list which can be used at a later point of time.
The credential DTO here is the object which maps to the database tables in the database and then
Connection conn=DBUtil.getConnection(constants.DB_DS_NAME);
Statement stmt=null;
stmt=conn.createStatement();
ResultSet rs= null;
Connection [] con=new Connection[schemaname.length];
int i,j;
String [] url=new String[schemaname.length];
String [] username=new String[schemaname.length];
String [] password=new String[schemaname.length];
List<CredentialDTO> creDTOlist=new ArrayList<CredentialDTO>();
String query1="insert into dba_project_master VALUES(9,'abc','abc','abc','abc',40)";
String query2="CREATE TABLE EMP(EMPNO NUMBER(4,0) NOT NULL ENABLE,ENAME VARCHAR2(10 BYTE),JOB VARCHAR2(9 BYTE), SAL NUMBER(7,2),DEPTNO NUMBER(2,0))";
try
{
for(i=0;i<schemaname.length;i++){
String query=" select * from dba_schema_details where schema_name="+DBUtil.enquoteString(schemaname[i]);
rs=stmt.executeQuery(query);
while(rs.next()){
CredentialDTO creDTO=new CredentialDTO();
creDTO.setSCHEMA_PK(rs.getString("SCHEMA_PK"));
creDTO.setSCHEMA_NAME(rs.getString("SCHEMA_NAME"));
creDTO.setPASSWORD(rs.getString("PASSWORD"));
creDTO.setORACLE_SID(rs.getString("ORACLE_SID"));
creDTO.setHOST_NAME(rs.getString("HOST_NAME"));
creDTO.setPORT_ID(rs.getString("PORT_ID"));
creDTOlist.add(creDTO);
}
}
System.out.println("creDTOlist size:"+creDTOlist.size());
//create URL for the schema name
int m=creDTOlist.size();
Iterator<CredentialDTO> LItr= creDTOlist.iterator();
String [] username1=new String[m];
String [] password1=new String[m];
i=0;
while(LItr.hasNext()){
System.out.println("iteration "+i);
CredentialDTO temp = LItr.next();
String URL="jdbc:oracle:thin:#"+temp.getHOST_NAME()+":"+temp.getPORT_ID()+":"+temp.getORACLE_SID();
System.out.println("URL:"+URL);
username1[i]=temp.getSCHEMA_NAME();
System.out.println("iteartion "+i+" username="+username1[i]);
password1[i]=temp.getPASSWORD();
System.out.println("iteartion "+i+" password="+password1[i]);
Class.forName("oracle.jdbc.OracleDriver");
con[i]=DriverManager.getConnection(URL, username1[i], password1[i]);
System.out.println("Connection Name:" +con[i]);
Statement st1=con[i].createStatement();
con[i].setAutoCommit(false);
st1.addBatch(query1);
st1.addBatch(query2);
int [] update=st1.executeBatch();
i++;
}
}
catch(Exception ex){
ex.printStackTrace();
}finally
{
if (conn != null) try{conn.close();} catch(SQLException ignore) {}
if (stmt!= null) try{stmt.close();} catch(SQLException ignore) {}
if (rs != null) try{rs.close();} catch(SQLException ignore) {}
}
return creDTOlist;
}
}
I am trying to connect to a SQL Server database, but I don't really know how to go about it using the info I was given. I was given the following:
Provider
DataSource
Persist Security Info
User ID
Initial Catalog
I have always connected via a web address or something, so I didn't really know how to go about using this. I am attempting to do this is Java using JDBC.
See here a wide list of examples, depending on which version you're using:
SQL Server 2000
SQL Server 2005
SQL Server 2008
To connect to MSSQL Server from a Java application, you need to use the JDBC API. The JDBC API provides classes and methods that connect to the database, load the appropriate driver, send SQL queries, retrieve results etc.
HOW TO CONNECT TO THE DATABASE: A ‘Connection’ object represents a connection with a database. To establish the connection, use the method ‘DriverManager.getConnection’. This method takes a string containing a URL which represents the database we are trying to connect to. Below is the sample code for establishing a connection:
private String DATABASE_URL = "jdbc:odbc:embedded_sql_app"; // establish connection to database
Connection connection = DriverManager.getConnection( DATABASE_URL,"sa","123" );
Detailed discussion about the Database URL and how to create it can be found in the resource provided at the end of this post.
QUERYING THE DATABASE: The JDBC API provides three interfaces for sending SQL statements to the database, and corresponding methods in the ‘Connection’ interface create instances of them. 1. Statement - created by the ‘Connection.createStatement’ methods. A ‘Statement’ object is used for sending SQL statements with no parameters.
2. PreparedStatement - created by the ‘Connection.prepareStatement methods’. A ‘PreparedStatement’ object is used for precompiled SQL statements. These can take one or more parameters as input arguments (IN parameters).
3. CallableStatement - created by the ‘Connection.prepareCall’ methods. ‘CallableStatement’ objects are used to execute SQL stored procedures from Java database applications.
RETRIEVING THE RESULT: A ‘ResultSet ‘is a Java object that contains the results of executing a SQL query. The data stored in a ‘ResultSet’ object is retrieved through a set of get methods that allows access to the various columns of the current row. The ‘ResultSet.next’ method is used to move to the next row of the ‘ResultSet’, making it the current row. The following code fragment executes a query that returns a collection of rows, with column ‘a’ as an ‘int’, column ‘b’ as a ‘String’, and column ‘c’ as a ‘float’:
java.sql.Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM Table1");
while (rs.next()) { // retrieve and print the values for the current row
int i = rs.getInt("a");
String s = rs.getString("b");
float f = rs.getFloat("c");
System.out.println("ROW = " + i + " " + s + " " + f);
}
This is just a brief introduction on how to interact with a database from Java. For more details on the items discussed above as well as information on passing parameters, executing stored procedures etc. please refer to the following resource: ( http://www.shahriarnk.com/Shahriar-N-K-Research-Embedding-SQL-in-C-Sharp-Java.html#Shahriar_N_Embedding_SQL_in_Java ) Here, you will also find information on how to interact with a database programmatically; i.e. without using SQL. Hope you find this useful.
Source:
http://www.shahriarnk.com/Shahriar-N-K-Research-Embedding-SQL-in-C-Sharp-Java.html