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Can you help me to find the error below in the ResultSet rs=stmt....? [duplicate]

This question already has an answer here:
ResultSet is not for INSERT query? Error message: Type mismatch: cannot convert from int to String
(1 answer)
Closed 5 years ago.
I am getting a error on the resultset rs part where netbeans shows the error as
incompatible types:int cannot be converted to resultset
Class.forName("java.sql.Driver");
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mysql?useSSL=false", "root", "abc");
Statement stmt = conn.createStatement();
String query = "SELECT * FROM patient WHERE Mobile_No='" + mobno + "';"; /*Get the value from the database*/
ResultSet rs = stmt.executeUpdate(query);/*Part where the error is appearing*/
while (rs.next()) {
String Name = rs.getString("Name");
String Age = rs.getString("Age");
String Mobile = rs.getString("Mobile_No");
String gender = rs.getString("Gender");
String symptoms = rs.getString("Symptoms");
model.addRow(new Object[]{Name, Age, Mobile, gender, symptoms});
}
rs.close();
stmt.close();
conn.close();

Use stmt.executeQuery(String sql), it returns ResultSet.

If you want a ResultSet returned you should use executeQuery, not executeUpdate.

The stmt.executeUpdate(query); doesn't fit for an SELECT query.
You need to replace it by stmt.executeQuery(query);

Well the method executeUpdate returns a int not a results set, seen in the documentation here: https://docs.oracle.com/javase/7/docs/api/java/sql/Statement.html#executeUpdate(java.lang.String)
the integer being return being either (1) the row count for SQL Data Manipulation Language (DML) statements or (2) 0 for SQL statements that return nothing
the method you are actually want to use is executeQuery and the documentation for that can be found at:
https://docs.oracle.com/javase/7/docs/api/java/sql/Statement.html#executeQuery(java.lang.String)

According the Javadoc (https://docs.oracle.com/javase/9/docs/api/java/sql/Statement.html#executeUpdate-java.lang.String-), stmt.executeUpdate(query); returns an int and not a ResultSet object.
From the Javadoc :
Returns:
either (1) the row count for SQL Data Manipulation Language (DML) statements or (2) 0 for SQL statements that return nothing
I think you must use stmt.executeQuery(query); instead, which return the ResultSet you expect. You're doing a SELECT and not an INSERT, UPDATE, or DELETE operation.

I believe people have already answered your question, which is statement.executeUpdate(query) returns the number of how many rows has been affected by executing the query, and you should use statement.executeQuery(query) instead ..
But this part String query = "SELECT * FROM patient WHERE Mobile_No = '" + mobno + "';" is very bad approach, it will leave the door opened for SQL injection, you should use PreparedStatement instead of Statement

get size of ResultSet by using SELECT COUNT(*)

I want to retrieve all the data from database, and at the same time, I want to know how many rows of data I get. And this is my SQL:
rs = s.executeQuery("SELECT COUNT(*), * FROM tblUser");
Is this a valid SQL statement? and after I retrieved all the data, how to set them into different variables? For example, I have a column called UserIDin the database, I can simply get it by using rs.getString('UserID'), but how to get the result of the COUNT(*)?

Your SQL is not valid. The ANSI standard way to do what you want uses window functions:
select count(*) over () as total_cnt,
u.*
from tblUser u;
This adds a new column to every row -- which seems to be what you want. There are other mechanisms, depending on the underlying database for doing this.

The results you request are not interrelated, so run two queries:
rs1 = s.executeQuery("SELECT COUNT(*) FROM tblUser");
rs2 = s.executeQuery("SELECT * FROM tblUser");
and retrieve the values (one only for rs1) the usual way.

You can do this to count the rows in resultset
String query = "Select * from tblUser";
rs = s.executeQuery(query);
public int getCount(ResultSet rs) {
int rows = 0;
while(rs.next()) {
i++;
}
return i;
}
This way you can get the resultset as well as count

Since you are already accessing the recordset within VBA probably the simplest was to return the count of the record set is to:
rs = s.executeQuery("SELECT * FROM tblUser");
If Not rs.EOF Then
' Important: You must move to the last record to
' obtain the count of the full recordset
rs.MoveLast
rsCount = rs.RecordCount
' Remember to Return to the First Record so that you can
' continue to use the recordset
rs.MoveFirst
End If

An alternative if your RDBMS doesn't support window functions
rs = s.executeQuery("SELECT B.cnt, U.*
FROM tblUser U,
(SELECT count(*) cnt FROM tblUser) B");

Getting the count of the resultset values [duplicate]

This question already has answers here:
How do I get the size of a java.sql.ResultSet?
(15 answers)
Closed 8 years ago.
I need your assistant and help in getting the count of the values which are available in the resultset. The resultset is having 22 records and in the below code, it is printing the count starting from 1 to 23. Is there any way to get the total no. of records as 22 (one value only) or by subtracting the last value from the first value?
My code is below:
while (rs.next())
{
count=0;
name1=rs.getString("name");
out.println(rs.getRow());
}
I tried to use rs.first() and rs.last() and it produced the below error:
java.sql.SQLException: Invalid operation for forward only resultset :
first
I tried to add the arguments to the createstatement, but the same exception is there:
conn.createStatement(rs.TYPE_SCROLL_INSENSITIVE, rs.CONCUR_READ_ONLY);
java.sql.SQLException: Invalid operation for forward only resultset :
last
Please help me in the above issue.

Try this:
int rowcount = 0;
if (rs.last()) {
rowcount = rs.getRow();
rs.beforeFirst();
}
EDIT:
You need to change the statement of your query like this so that you can use the rs.last()
Statement stmt = con.createStatement(rs.TYPE_SCROLL_INSENSITIVE);
ResultSet rs = stmt.executeQuery("Your query");
Check Oracle Docs

You can use MySQL's count(*)
try{
Statement stmt = connection.createStatement();
String selectquery = "select count(*) from YourTable";
ResultSet rs = stmt.executeQuery(selectquery);
rs.next();
System.out.println("Amount of rows :" + rs.getInt(1));
}
If you wanna count rows based on "name", then
try{
Statement stmt = connection.createStatement();
String selectquery = "select count(name) from YourTable";
ResultSet rs = stmt.executeQuery(selectquery);
rs.next();
System.out.println("Amount of rows :" + rs.getInt(1));
}

Value from last inserted row in DB [duplicate]

This question already has answers here:
How to get a value from the last inserted row? [duplicate]
(14 answers)
Closed 9 years ago.
Is there some way to get a value from the last inserted row?
I am inserting a row where the PK will automatically increase due to sequence created, and I would like to get this sequence number. Only the PK is guaranteed to be unique in the table.
I am using Java with a JDBC and Oracle.
I forgot to add that I would like to retrieve this value using the resultset below. (I have tried this with mysql and it worked successfully, but I had to switch over to Oracle and now I get a string representation of the ID and not the actually sequence number)
Statement stmt = conn.createStatement();
stmt.executeUpdate(insertCmd, Statement.RETURN_GENERATED_KEYS);
stmt.RETURN_GENERATED_KEYS;
ResultSet rs = stmt.getGeneratedKeys();
if(rs.next()){
log.info("Successful insert");
id = rs.getString(1);
}
The above snippet would return the column int value stored in a mysql table. But since I have switched over to Oracle, the value returned is now a strange string value.

What you're trying to do is take advantage of the RETURNING clause. Let's setup an example table and sequence:
CREATE TABLE "TEST"
( "ID" NUMBER NOT NULL ENABLE,
"NAME" VARCHAR2(100 CHAR) NOT NULL ENABLE,
CONSTRAINT "PK_TEST" PRIMARY KEY ("ID")
);
CREATE SEQUENCE SEQ_TEST;
Now, your Java code should look like this:
String insertSql = "BEGIN INSERT INTO TEST (ID, NAME) VALUES (SEQ_TEST.NEXTVAL(), ?) RETURNING ID INTO ?; END;";
java.sql.CallableStatement stmt = conn.prepareCall(insertSql);
stmt.setString(1, "John Smith");
stmt.registerOutParameter(2, java.sql.Types.VARCHAR);
stmt.execute();
int id = stmt.getInt(2);

This is not consistent with other databases but, when using Oracle, getGeneratedKeys() returns the ROWID for the inserted row when using Statement.RETURN_GENERATEDKEYS. So you need to use the oracle.sql.ROWID proprietary type to "read" it:
Statement stmt = connection.createStatement();
stmt.executeUpdate(insertCmd, Statement.RETURN_GENERATED_KEYS);
ResultSet rs = stmt.getGeneratedKeys();
oracle.sql.ROWID rid = (oracle.sql.ROWID) rs.getObject(1);
But this won't give you the generated ID of the PK. When working with Oracle, you should either use the method executeUpdate(String sql, int[] columnIndexes) or executeUpdate(String sql, String[] columnNames) instead of executeUpdate(String sql, int autoGeneratedKeys) to get the generated sequence value. Something like this (adapt the value to match the index or the name of your primary key column):
stmt.executeUpdate(INSERT_SQL, new int[] {1});
ResultSet rs = stmt.getGeneratedKeys();
Or
stmt.executeUpdate(INSERT_SQL, new String[] {"ID"});
ResultSet rs = stmt.getGeneratedKeys();
While digging a bit more on this, it appears that this approach is shown in the Spring documentation (as mentioned here) so, well, I guess it can't be totally wrong. But, unfortunately, it is not really portable and it may not work on other platforms.

You should use ResultSet#getLong() instead. If in vain, try ResultSet#getRowId() and eventually cast it to oracle.sql.ROWID. If the returned hex string is actually the ID in hexadecimal flavor, then you can try converting it to decimal by Long#valueOf() or Integer#valueOf().
Long id = Long.valueOf(hexId, 16);
That said, Oracle's JDBC driver didn't support ResultSet#getGeneratedKeys() for a long time and is still somewhat troublesome with it. If you can't get that right, then you need to execute a SELECT CURRVAL(sequencename) on the same statement as you did the insert, or a new statement inside the same transaction, if it was a PreparedStatement. Basic example:
public void create(User user) throws SQLException {
Connection connection = null;
PreparedStatement preparedStatement = null;
Statement statement = null;
ResultSet generatedKeys = null;
try {
connection = daoFactory.getConnection();
preparedStatement = connection.prepareStatement(SQL_INSERT);
preparedStatement.setValue(1, user.getName());
// Set more values here.
int affectedRows = preparedStatement.executeUpdate();
if (affectedRows == 0) {
throw new SQLException("Creating user failed, no rows affected.");
}
statement = connection.createStatement();
generatedKeys = statement.executeQuery(SQL_CURRVAL);
if (generatedKeys.next()) {
user.setId(generatedKeys.getLong(1));
} else {
throw new SQLException("Creating user failed, no generated key obtained.");
}
} finally {
close(generatedKeys);
close(statement);
close(preparedStatement);
close(connection);
}
}
Oh, from your code example, the following line
stmt.RETURN_GENERATED_KEYS;
is entirely superfluous. Remove it.
You can find here another example which I posted before about getting the generated keys, it uses the normal getGeneratedKeys() approach.

How to get a value from the last inserted row? [duplicate]

This question already has answers here:
How to get the insert ID in JDBC?
(14 answers)
Closed 7 years ago.
Is there some way to get a value from the last inserted row?
I am inserting a row where the PK will automatically increase, and I would like to get this PK. Only the PK is guaranteed to be unique in the table.
I am using Java with a JDBC and PostgreSQL.

With PostgreSQL you can do it via the RETURNING keyword:
PostgresSQL - RETURNING
INSERT INTO mytable( field_1, field_2,... )
VALUES ( value_1, value_2 ) RETURNING anyfield
It will return the value of "anyfield". "anyfield" may be a sequence or not.
To use it with JDBC, do:
ResultSet rs = statement.executeQuery("INSERT ... RETURNING ID");
rs.next();
rs.getInt(1);

See the API docs for java.sql.Statement.
Basically, when you call executeUpdate() or executeQuery(), use the Statement.RETURN_GENERATED_KEYS constant. You can then call getGeneratedKeys to get the auto-generated keys of all rows created by that execution. (Assuming your JDBC driver provides it.)
It goes something along the lines of this:
Statement stmt = conn.createStatement();
stmt.execute(sql, Statement.RETURN_GENERATED_KEYS);
ResultSet keyset = stmt.getGeneratedKeys();

If you're using JDBC 3.0, then you can get the value of the PK as soon as you inserted it.
Here's an article that talks about how : https://www.ibm.com/developerworks/java/library/j-jdbcnew/
Statement stmt = conn.createStatement();
// Obtain the generated key that results from the query.
stmt.executeUpdate("INSERT INTO authors " +
"(first_name, last_name) " +
"VALUES ('George', 'Orwell')",
Statement.RETURN_GENERATED_KEYS);
ResultSet rs = stmt.getGeneratedKeys();
if ( rs.next() ) {
// Retrieve the auto generated key(s).
int key = rs.getInt(1);
}

Since PostgreSQL JDBC driver version 8.4-701 the PreparedStatement#getGeneratedKeys() is finally fully functional. We use it here almost one year in production to our full satisfaction.
In "plain JDBC" the PreparedStatement needs to be created as follows to make it to return the keys:
statement = connection.prepareStatement(SQL, Statement.RETURN_GENERATED_KEYS);
You can download the current JDBC driver version here (which is at the moment still 8.4-701).

The sequences in postgresql are transaction safe. So you can use the
currval(sequence)
Quote:
currval
Return the value most recently obtained by nextval for this sequence
in the current session. (An error is
reported if nextval has never been
called for this sequence in this
session.) Notice that because this is
returning a session-local value, it
gives a predictable answer even if
other sessions are executing nextval
meanwhile.

Here is how I solved it, based on the answers here:
Connection conn = ConnectToDB(); //ConnectToDB establishes a connection to the database.
String sql = "INSERT INTO \"TableName\"" +
"(\"Column1\", \"Column2\",\"Column3\",\"Column4\")" +
"VALUES ('value1',value2, 'value3', 'value4') RETURNING
\"TableName\".\"TableId\"";
PreparedStatement prpState = conn.prepareStatement(sql);
ResultSet rs = prpState.executeQuery();
if(rs.next()){
System.out.println(rs.getInt(1));
}

If you are using Statement, go for the following
//MY_NUMBER is the column name in the database
String generatedColumns[] = {"MY_NUMBER"};
Statement stmt = conn.createStatement();
//String sql holds the insert query
stmt.executeUpdate(sql, generatedColumns);
ResultSet rs = stmt.getGeneratedKeys();
// The generated id
if(rs.next())
long key = rs.getLong(1);
If you are using PreparedStatement, go for the following
String generatedColumns[] = {"MY_NUMBER"};
PreparedStatement pstmt = conn.prepareStatement(sql,generatedColumns);
pstmt.setString(1, "qwerty");
pstmt.execute();
ResultSet rs = pstmt.getGeneratedKeys();
if(rs.next())
long key = rs.getLong(1);

Use sequences in postgres for id columns:
INSERT mytable(myid) VALUES (nextval('MySequence'));
SELECT currval('MySequence');
currval will return the current value of the sequence in the same session.
(In MS SQL, you would use ##identity or SCOPE_IDENTITY())

PreparedStatement stmt = getConnection(PROJECTDB + 2)
.prepareStatement("INSERT INTO fonts (font_size) VALUES(?) RETURNING fonts.*");
stmt.setString(1, "986");
ResultSet res = stmt.executeQuery();
while (res.next()) {
System.out.println("Generated key: " + res.getLong(1));
System.out.println("Generated key: " + res.getInt(2));
System.out.println("Generated key: " + res.getInt(3));
}
stmt.close();

Don't use SELECT currval('MySequence') - the value gets incremented on inserts that fail.

For MyBatis 3.0.4 with Annotations and Postgresql driver 9.0-801.jdbc4 you define an interface method in your Mapper like
public interface ObjectiveMapper {
#Select("insert into objectives" +
" (code,title,description) values" +
" (#{code}, #{title}, #{description}) returning id")
int insert(Objective anObjective);
Note that #Select is used instead of #Insert.

for example:
Connection conn = null;
PreparedStatement sth = null;
ResultSet rs =null;
try {
conn = delegate.getConnection();
sth = conn.prepareStatement(INSERT_SQL);
sth.setString(1, pais.getNombre());
sth.executeUpdate();
rs=sth.getGeneratedKeys();
if(rs.next()){
Integer id = (Integer) rs.getInt(1);
pais.setId(id);
}
}
with ,Statement.RETURN_GENERATED_KEYS);" no found.

Use that simple code:
// Do your insert code
myDataBase.execSQL("INSERT INTO TABLE_NAME (FIELD_NAME1,FIELD_NAME2,...)VALUES (VALUE1,VALUE2,...)");
// Use the sqlite function "last_insert_rowid"
Cursor last_id_inserted = yourBD.rawQuery("SELECT last_insert_rowid()", null);
// Retrieve data from cursor.
last_id_inserted.moveToFirst(); // Don't forget that!
ultimo_id = last_id_inserted.getLong(0); // For Java, the result is returned on Long type (64)

If you are in a transaction you can use SELECT lastval() after an insert to get the last generated id.