Develop Reference

How to convert DB2 binary data to UTF-8 at query level

I am connected to IBM DB2 database with java but data is stored as binary format in database so when I fetch any value it comes as binary or hexdecimal format. How can I convert this in binary data in utf-8 at query level.
Sample code to fetch data -
String sql = "SELECT poMast.ORDNO from AMFLIBL.POMAST AS poMast ";
Class.forName("com.ddtek.jdbc.db2.DB2Driver");
String url = "jdbc:datadirect:db2://hostname:port;DatabaseName=dbName;";
Connection con = DriverManager.getConnection(url, "username","password");
PreparedStatement preparedStatement = con.prepareStatement(sql);
ResultSet rs = preparedStatement.executeQuery();
System.out.println("ResultSet : \n");
System.out.println(" VNDNO");
while (rs.next())
{
System.out.println(rs.getString("ORDNO"));
}

You probably need to use the CAST expression:
SELECT CAST(poMast.ORDNO as VARCHAR(50)) from AMFLIBL.POMAST AS poMast
Adjust the VARCHAR length to your needs. The string is in the database codepage (often UTF-8 these days) and converted to the client/application codepage when fetched.

you can "cast" the result from your select to utf8 like below.
String sql = "SELECT poMast.ORDNO, CAST(poMast.ORDNO AS VARCHAR(255) CCSID UNICODE) FROM AMFLIBL.POMAST AS poMast ";
src: cast db2

In my case, somehow bad UTF-8 data had gotten into varchars in a 1208/UTF-8 DB. Prior to conversion, when querying such data via the JDBC driver, the DB returned -4220 via the JDBC driver. This is fixable at the JDBC driver level by adding this property:
java -Ddb2.jcc.charsetDecoderEncoder=3 MyApp
see:
https://www.ibm.com/support/pages/sqlexception-message-caught-javaiocharconversionexception-and-errorcode-4220
The Db2 LUW Command Line Processor fixed it long ago as an APAR, so this error is only seen via the JDBC driver when the above property is not set.
But, if you want to fix the data in the db, this works:
update <table_name> set <bad_data_col> = cast(cast( <bad_data_col> as vargraphic) as varchar);
1st db2 treats (casts) the bad data as a binary where "anything goes" and then converts (casts) it back to valid UTF-8. After the casts, the JDBC driver shows the same result with or without the special property set and returns no errors.

Insert data to sql using java issue

I'm facing an issue with insertion to SQL database from java code.
I'm using INSERT sql query using the java code to enter the data from XML file to SQL database.
You may suppose column named "Description".
Imagine there is a record in XML which contains apostrophe ('). The program crashes due to the error caused by the apostrophe which is included in the data.
I know that manually we can add another apostrophe and make it work, but imagine data of 10.000 records, how can we handle this issue?

Don't do this (string concatenation):
String sql = "insert into MyTable (description) values ('" + value + "')";
Statement st = connection.createStatement();
st.executeUpdate(sql);
Do do this (prepared statement):
PreparedStatement ps = connection.prepareStatement(
"insert into MyTable (description) values (?)"
);
ps.setString(1, value);
pt.executeUpdate();
The value will get correctly escaped for you. Not only does this protect against mishaps like the one you mentioned, it also helps defend you from SQL injection attacks.
Humorous illustration:
Source

You have two options, you should use PreparedStatement and bind your parameter(s). Or, if you really, really, want - you could use StringEscapeUtils.escapeSql(str).

JDBC PreparedStatement with "?" in the column name

I am using a JDBC connection to fetch data from an Access database.
The database design is not my control. In the database there are columns that have "?" included in their names, for example: Open?, Paid?, and lots more.
When I try to fetch data with a PreparedStatement it gives me an error. The query is:
SELECT Open? FROM tblJobList WHERE WeekEnding=?
I also tried to use brackets like [Open?], but the result is the same.
The error I receive is "Too few parameters ..." as I am pushing only one parameter into the PreparedStatement.
I can not use normal statement because of WeekEnding=? as this value is a Timestamp and I could not manage to work it with Statement. Only prepared statement works here.
Can anyone tell me how to use these kind of column names in a PreparedStatement?

use the " character
"SELECT \"Open?\" FROM tblJobList WHERE WeekEnding=?"
tested this against oracle and appears to work with mssqlserver
How to select a column in SQL Server with a special character in the column name?

Just to update this for current technologies:
While the JDBC-ODBC Bridge and Access ODBC were unable to handle a PreparedStatement with a column name containing a question mark, the UCanAccess JDBC driver handles it just fine, as can be confirmed with the following code:
String connectionUrl = "jdbc:ucanaccess://C:/Users/Public/UCanAccessTest.accdb";
Connection conn = DriverManager.getConnection(connectionUrl);
String sql = "SELECT ID, [Open?] FROM tblJobList WHERE WeekEnding=?";
PreparedStatement ps = conn.prepareStatement(sql);
ps.setDate(1, java.sql.Date.valueOf("2016-01-01"));
ResultSet rs = ps.executeQuery();
while (rs.next()) {
System.out.printf("%d: %s%n", rs.getInt("ID"), rs.getBoolean("Open?"));
}
conn.close();
For more information on UCanAccess, see
Manipulating an Access database from Java without ODBC

I am not sure but you can try // to escape the special meaning of ? and to use it as a normal character. Like:
"SELECT Open//? FROM tblJobList WHERE WeekEnding=?"
You can get something similar to your problem here:
Round bracket in string with JDBC prepared statement

Escaping quotes in MSSQL is done by a double quote, so a '' or a "" will produce one escaped ' and ", respectively.

Java: insert accented characters in mysql

If I have this query from java:
String query="insert into user (..., name, ...) values (..., 'à', ...)";
Class.forName("com.mysql.jdbc.Driver").newInstance();
Connection con = DriverManager.getConnection("jdbc:mysql://localhost/Spinning?user=root");
PreparedStatement prest = con.prepareStatement(query);
prest.executeUpdate();
In the db I will have a strange character: a diamond with a question mark inside.
Is there any solution to this problem?

Change your connection url to the following:
jdbc:mysql://localhost/Spinning?user=root&useUnicode=true&characterEncoding=utf8

Verify the character set you are using in MySQL DB. You can try "SHOW CREATE TABLE xxxx" to print the table DDL with charset being used.
Verify the character set you are using in JDBC driver. If using MySQL ConnectorJ, you can set charset in the JDBC url.

How can I insert an XML document in PostgreSQL in Java?

I have a table in Postgresql
DROP TABLE xml_docs;
CREATE TABLE xml_docs(
id serial PRIMARY KEY,
cad_number character(50),
gkuzu_name character(50),
gkuzu xml,
rreq_name character(50),
rreq xml
)
I use JDBC for data base connection. And i want to insert whole xml document in table.
How can i make this?
UPDATE
Okey. i try
String sql = "INSERT INTO xml_docs(cad_number,gkuzu_name,gkuzu,rreq_name,rreq) VALUES(?,?,?,?,?)";
PreparedStatement stmt = ce.prepareStatement(sql);
stmt.setString(1, "11:33:5464563");
stmt.setString(2, xml_gkuzu.getName());
stmt.setString(3, xml_gkuzu.toString());
stmt.setString(4, xml_rreq.getName());
stmt.setString(5, xml_rreq.toString());
stmt.executeQuery();
ce.close();
se.close();
and get exeption
Exception in thread "main" org.postgresql.util.PSQLException: ERROR: column "gkuzu" is of type xml but expression is of type character varying
Подсказка: You will need to rewrite or cast the expression.
Whats wrong?
UPDATE 2
When i try do this
String sql1 = "INSERT INTO xml_docs(cad_number,gkuzu_name,gkuzu,rreq_name,rreq) VALUES(11335464563,"+xml_gkuzu.getName()+",XMLPARSE("+xml_gkuzu.toString()+"),"+xml_rreq.getName()+",XMLPARSE("+xml_rreq.toString()+"))";
i get exeption
Exception in thread "main" org.postgresql.util.PSQLException: ERROR: syntax error at or near "bf48e000b0"

I'm not sure, but try this:
First convert your XML to a Java String.
Then create an insert statement und use the XMLPARSE method of PostgreSQL to convert your value to the xml type of PostgreSQL:
INSERT INTO xml_docs(id, gkuzu) VALUES (1, XMLPARSE('<foo><bar>Hello</bar></foo>'));
See: http://wiki.postgresql.org/wiki/XML_Support
UPDATE:
Java code example:
String sql = "INSERT INTO xml_docs(id, gkuzu) VALUES (?, XMLPARSE(?))";
[...]
stmt.setString(2, "<foo>Hello World!</foo>");
This should create this statement:
INSERT INTO xml_docs(id, gkuzu) VALUES (1, XMLPARSE('<foo>Hello World!</foo>'));

Instead of rewriting the insert statement using PostgreSQL-proprietary syntax, you could use JDBC 4 SQLXML:
String xml = xml_gkuzu.toString();
SQLXML sqlxml = connection.createSQLXML();
sqlxml.setString(xml);
stmt.setSQLXML(3, sqlxml);

Though postgres has native XML Data type, from java end, You can handle with Plain strings.
You can convert your xml document to String and insert, It should work.
UPDATE:
After looking at your error, You need to pass an additional variable to the server through driver URL.
jdbc:postgresql://localhost/test?stringtype=unspecified
or
jdbc:postgresql://localhost/test?user=user&password=pass&stringtype=unspecified
The extra param stringtype=unspecified will remove the type check for the input strings.

An update to the accepted answer if you do not have Postgres built with libxml support:
Java code example:
String sql = "INSERT INTO xml_docs(id, gkuzu) VALUES (?, XML(?))";
[...]
stmt.setString(2, "<foo>Hello World!</foo>");
This should create this statement:
INSERT INTO xml_docs(id, gkuzu) VALUES (1, XML('<foo>Hello World!</foo>'));
Thus for version 9.0 and greater you may want to switch XMLPARSE ==> XML. Otherwise you will need special support for XMLPARSE
From Postgres Documentation:
The function-like expressions xmlparse and xmlserialize for converting to and from type xml are not repeated here. Use of most of these functions requires the installation to have been built with configure --with-libxml.