I am preparing a SQL statement from values passed through a query string. ( I am using the Play! framework. Basically what I'm running into (not really an issue just something I don't like very much) is that when I want to use ? in the SQL string and set them later with dynamic values.
This is what I have:
String sql = "SELECT * FROM foobar_table WHERE";
if ( foo != 0 )
sql += " AND foo=?";
if ( !bar )
sql += " AND bar=?";
try{
PreparedStatement getStmt = con.prepareStatement(sql);
if ( foo != 0 )
getStmt.setInt(1,foo);
if ( foo != 0 && !bar )
getStmt.setBoolean(2, bar);
else
getStmt.setBoolean(1, bar);
} catch (SQLException e ){
e.printStackTrace();
}
This does work but as you can see not very intuitive. It's OK when there are 2 dynamic values but when you get up to 5 or 6 this would just get ridiculous.
Is there an easier way of doing this to make it more flexible so that I would know how to fill in all the ? in a better fashion?
An example (was too long for comment):
String sql = "SELECT * FROM foobar_table WHERE 1 = 1 ";
ArrayList paramList = new ArrayList();
if ( foo != 0 ) {
sql += " AND foo=?";
paramList.add(foo);
}
if ( !bar ) {
sql += " AND bar=?";
paramList.add(bar);
}
try{
PreparedStatement getStmt = con.prepareStatement(sql);
int index = 1;
for (Object param : paramList) {
getStmt.setObject(index, param);
index++;
}
// execute
} catch (SQLException e ){
e.printStackTrace();
}
Something like this maybe (just rough code but you get the idea):
class Param{
final int type;
final Object value;
Param(int type, Object value){
this.type = type;
this.value = value;
}
}
final List<Param> params = new ArrayList<>();
final StringBuilder sql = new StringBuilder("SELECT * FROM bcu_venue_events WHERE 1=1");
int foo = 0;
boolean bar = true;
if (foo != 0){
sql.append(" AND foo=?");
params.add(new Param(Types.INTEGER, foo));
}
if (!bar){
sql.append(" AND bar=?");
params.add(new Param(Types.BOOLEAN, bar));
}
try(Connection conn = null; PreparedStatement getStmt = conn.prepareStatement(sql.toString())) {
for(int i = 0; i < params.size(); i++){
Param p = params.get(i);
getStmt.setObject(i + 1, p.value, p.type);
}
} catch (SQLException e) {
e.printStackTrace();
}
How about this:
String sql = "SELECT * FROM foobar_table WHERE 1=1";
if ( foo != 0 )
sql += " AND foo=" + foo;
if ( !bar )
sql += " AND bar=" + bar;
try{
PreparedStatement getStmt = con.prepareStatement(sql);
} catch (SQLException e ){
e.printStackTrace();
}
Related
I create this code for get column name in sql databases. But now I ant to modify above code for get all table data with column name. Then get all data and convert to jsonarray and pass. How I modify this code for get all table data with column name.
#Override
public JSONArray getarray(String sheetName) {
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con = (Connection) DriverManager.getConnection("jdbc:mysql://localhost/test", "root", "");
con.setAutoCommit(false);
PreparedStatement pstm = null;
Statement stmt = null;
//-----------------------Drop earliye table -------------------------------------------------------------
try {
String sqldrop = "select COLUMN_NAME from information_schema.COLUMNS where TABLE_NAME='" + sheetName.replaceAll(" ", "_") + "'";
System.out.println(sqldrop);
PreparedStatement mypstmt = con.prepareStatement(sqldrop);
ResultSet resultSet = mypstmt.executeQuery();
JSONArray jsonArray = new JSONArray();
while (resultSet.next()) {
int total_rows = resultSet.getMetaData().getColumnCount();
JSONObject obj = new JSONObject();
for (int i = 0; i < total_rows; i++) {
String columnName = resultSet.getMetaData().getColumnLabel(i + 1).toLowerCase();
Object columnValue = resultSet.getObject(i + 1).toString().replaceAll("_", " ");
// if value in DB is null, then we set it to default value
if (columnValue == null) {
columnValue = "null";
}
/*
Next if block is a hack. In case when in db we have values like price and price1 there's a bug in jdbc -
both this names are getting stored as price in ResulSet. Therefore when we store second column value,
we overwrite original value of price. To avoid that, i simply add 1 to be consistent with DB.
*/
if (obj.has(columnName)) {
columnName += "1";
}
obj.put(columnName, columnValue);
}
jsonArray.put(obj);
}
mypstmt.close();
con.commit();
return jsonArray;
} catch (Exception e) {
System.out.println("There is no exist earlyer databases table!..... :( :( :( **************** " + sheetName.replaceAll(" ", "_"));
}
//----------------------------------------------------------------------------
} catch (ClassNotFoundException e) {
System.out.println(e);
} catch (SQLException ex) {
Logger.getLogger(PassArrayDaoImpl.class.getName()).log(Level.SEVERE, null, ex);
}
System.out.println("%%%%%%%%%%");
return null;
}
My target is get all data with column name and above data pass html page as a json. So if you have any method for get all data with column name is suitable for me.
// code starts here
// This method retrieves all data from a mysql table...
public void retrieveAllData( String host, String user, String pass, String query) {
JTextArea textArea = new JTextArea();
try(
Connection connection = DriverManager.getConnection( host, user, pass )
Statement statement = connection.createStatement()
ResultSet resultSet = statement.executeQuery(query)) {
ResultSetMetaData metaData = resultSet.getMetaData();
int totalColumns = metaData.getColumnCount();
for( int i = 1; i <= totalColumns; i++ ) {
textArea.append( String.format( "%-8s\t", metaData.getColumnName(i) ) );
}
textArea.append( "\n" );
while( resultSet.next() ) {
for( int i = 1; i <= totalColumns; i++ ) {
Object object = resultSet.getObject(i).toString();
textArea.append( String.format("%-8s\t", object) );
}
textArea.append( "\n" );
}
}
}
See Below. rs.getString("tags") is subquery with more than 1 row. I want to iterate that subquery(rs.getString("tags") ---- Like rs.next().
while (rs.next()) {
emailDto emaildto = new emailDto();
emaildto.setMid(rs.getInt("id"));
emaildto.setSub(rs.getString("sub"));
emaildto.setMessage(rs.getString("message"));
while(rs.getString("tags").next()){
arrtags[i] = rs.getString(1);
}
emaildto.setTags(arrtags);
rs.getString("tags") does not work --- and contain more than 1 rows. How to extract it. Is there any technique?
Try something like this:
Array tagsArray = rs.getArray("tags");
String[] tags = (String[])tagsArray.getArray();
this is not answer. this is complete code
List emails = new ArrayList();
String listQuery = "select mid, sub, message, "
+ " (select emailid from sub_ids where sub_ids.messageid= sub_mail_list.mid ) // this query fetch more than one row.
as refid"
+ " from sub_mail_list";
PreparedStatement ps = null;
ResultSet rs;
try {
ps = DatabaseConnectionUtil.getConnection().prepareStatement(
listQuery);
rs = ps.executeQuery(listQuery);
while (rs.next()) {
emailDto emaildto = new emailDto();
emaildto.setMid(rs.getInt("mid"));
emaildto.setSub(rs.getString("sub"));
emaildto.setMessage(rs.getString("message"));
Array tagsArray = rs.getArray("refid");
List<vtbDto> vtbdtosvr = new ArrayList<vtbDto>();
int[] tags = (int[])tagsArray.getArray();
for (int i = 0; i < tags.length; i++) {
vtbDto vtbdto = new vtbDto();
vtbdto.setRefid(tags[i]);
vtbdtosvr.add(vtbdto);
}
emaildto.setAr(tagsArray);
emails.add(emaildto);
}
} catch (Exception ex) {
ex.printStackTrace();
} finally {
DatabaseConnectionUtil.closeAll(ps);
}
return emails;
And this is code to print function
List emailDtos = emaildao.getAllemails();
for (emailDto emailDto2 : emailDtos) {
System.out.println( emailDto2.getMid());
System.out.println( emailDto2.getSub());
System.out.println( emailDto2.getMessage());
List<vtbDto> vtbdtos= emailDto2.getVtbdtolst();
for (vtbDto vtbdto2 : vtbdtos) {
System.out.print(vtbdto2.getRefid() + ", ");
}
}
and the console print "Subquery returns more than 1 row";
I have a JFrame that has 3 JTextfields and 2 JDatechooser, what I am trying to do is if only one JTextfield has something typed in it and I press the search button, then I will be able to retrieve the data to JTable, but the problem is I have to fill out all JTextFileds and JDatechooser in order to retrieve data. My idea is to ignore null JTextfields and JTdatechooser if only one JTextfield has the keyword I want ?? Any suggestions ?? Thanks in advance,
public ArrayList<BillsRecord> getBillRecordByID(int EmpCode, String Fname, String Lname, String sDate, String eDate) throws SQLException {
String sql = "SELECT B.DATE AS DT, B.EMP_ID, E.FNAME, E.LNAME, MONEY_SENT, RENT, PHONE, GAS, ELECTRICITY, INTERNET, OTHER"
+ " FROM EMPLOYEE E INNER JOIN BILLS B ON E.EMP_ID = B.EMP_ID"
+ " WHERE B.EMP_ID = ? "
+ " OR E.FNAME = ? "
+ " OR E.LNAME = ? "
+ " OR DATE BETWEEN ? AND ? "
+ " ORDER BY B.DATE";
DBConnection con = new DBConnection();
Connection connect = con.getConnection();
PreparedStatement ps = null;
ArrayList<BillsRecord> records = new ArrayList<>();
try {
ps = connect.prepareStatement(sql);
ps.setInt(1, EmpCode);
ps.setString(2, Fname);
ps.setString(3, Lname);
ps.setString(4, sDate);
ps.setString(5, eDate);
ResultSet rs = ps.executeQuery();
if (rs.next()) {
BillsRecord billrec = new BillsRecord();
billrec.setDATE(rs.getString("DT"));
billrec.setEMP_ID(rs.getInt("EMP_ID"));
billrec.setFNAME(rs.getString("FNAME"));
billrec.setLNAME(rs.getString("LNAME"));
billrec.setMONEY_SENT(rs.getDouble("MONEY_SENT"));
billrec.setRENT(rs.getDouble("RENT"));
billrec.setPHONE(rs.getDouble("PHONE"));
billrec.setGAS(rs.getDouble("GAS"));
billrec.setELECTRICITY(rs.getDouble("ELECTRICITY"));
billrec.setINTERNET(rs.getDouble("INTERNET"));
billrec.setOTHER(rs.getDouble("OTHER"));
records.add(billrec);
return records;
}
} catch (SQLException e) {
System.out.println(e.toString());
} finally {
if (ps != null) {
ps.close();
}
if (connect != null) {
connect.close();
}
}
return null;
}
private void search() {
try {
JTextField stxt = ((JTextField) startdatetxt.getDateEditor().getUiComponent());
String sDATE = stxt.getText().trim();
JTextField etxt = ((JTextField) enddatetxt.getDateEditor().getUiComponent());
String eDATE = etxt.getText().trim();
int EMP_ID = Integer.parseInt(this.empidtxt.getText().trim());
String FNAME = this.firstnametxt.getText().trim();
String LNAME = this.lastnametxt.getText().trim();
BillRecordDao billrecdao = new BillRecordDao();
ArrayList<BillsRecord> records = billrecdao.getBillRecordByID(EMP_ID, FNAME, LNAME, sDATE, eDATE);
Object[] tableColumnName = new Object[11];
tableColumnName[0] = "Date";
tableColumnName[1] = "H.License";
tableColumnName[2] = "First Name";
tableColumnName[3] = "Last Name";
tableColumnName[4] = "MONEY SENT";
tableColumnName[5] = "RENT";
tableColumnName[6] = "PHONE";
tableColumnName[7] = "GASE";
tableColumnName[8] = "ELECTRICITY";
tableColumnName[9] = "INTERNET";
tableColumnName[10] = "OTHER";
DefaultTableModel tbd = new DefaultTableModel();
tbd.setColumnIdentifiers(tableColumnName);
this.BillsSummaryTable.setModel(tbd);
Object[] RowRec = new Object[11];
for (int i = 0; i < records.size(); i++) {
RowRec[0] = records.get(i).getDATE();
RowRec[1] = records.get(i).getEMP_ID();
RowRec[2] = records.get(i).getFNAME().toUpperCase();
RowRec[3] = records.get(i).getLNAME().toUpperCase();
RowRec[4] = records.get(i).getMONEY_SENT();
RowRec[5] = records.get(i).getRENT();
RowRec[6] = records.get(i).getPHONE();
RowRec[7] = records.get(i).getGAS();
RowRec[8] = records.get(i).getELECTRICITY();
RowRec[9] = records.get(i).getINTERNET();
RowRec[10] = records.get(i).getOTHER();
tbd.addRow(RowRec);
}
} catch (SQLException e) {
System.out.println(e.toString());
}
}
Basically, you need to create a variable/dynamic query based on the available values
Now, you can do this using something like StringBuilder or even storing each query element in a List or array, but you always end up with the "trailing OR" problem (you need to know when you've got to the last element and not append the "OR" to the String or remove the trailing "OR" from the resulting String). While not difficult, it's just a pain.
However, if you're using Java 8, you can use StringJoiner!
StringJoiner sj = new StringJoiner(" OR ");
String sql = "SELECT B.DATE AS DT, B.EMP_ID, E.FNAME, E.LNAME, MONEY_SENT, RENT, PHONE, GAS, ELECTRICITY, INTERNET, OTHER"
+ " FROM EMPLOYEE E INNER JOIN BILLS B ON E.EMP_ID = B.EMP_ID"
+ " WHERE ";
List values = new ArrayList();
// EmpCode MUST be a Integer, so it can be null
if (EmpCode != null) {
sj.add("B.EMP_ID = ?");
values.add(EmpCode);
}
if (FName != null) {
sj.add("E.FNAME = ?");
values.add(FName);
}
if (LName != null) {
sj.add("E.LNAME = ?");
values.add(LName);
}
if (sDate != null && eDate != null) {
sj.add("DATE BETWEEN ? AND ?");
values.add(sDate);
values.add(eDate);
}
sql += sj.toString();
Connection connect = null;
try (PreparedStatement ps = connect.prepareStatement(sql)) {
for (int index = 0; index < values.size(); index++) {
ps.setObject(index + 1, values.get(index));
}
try (ResultSet rs = ps.executeQuery()) {
if (rs.next()) {
//...
}
}
} catch (SQLException exp) {
exp.printStackTrace();
}
You might also like to have a look at The try-with-resources Statement and have a read through Code Conventions for the Java TM Programming Language, it will make it easier for people to read your code and for you to read others
i am using below simple query to get the result for testing purpose.
qName = "select total_requests from (select 10000 as total_requests from dual)"; //this can be dynamic query
preStatement = connection.prepareStatement(qName);
ParameterMetaData pmd = preStatement.getParameterMetaData();
int stmtCount = pmd.getParameterCount();
int paramsCount = params == null ? 0 : params.length;
for (int i = 0; i < params.length; i++) {
if (params[i] != null) {
preStatement.setObject(i + 1, params[i]);
} else {
int sqlType = Types.VARCHAR;
if (!paramValid) {
try {
sqlType = pmd.getParameterType(i + 1);
} catch (SQLException e) {
paramValid = true;
}
}
preStatement.setNull(i + 1, sqlType);
}
}
ResultSet rs = preStatement.executeQuery();
once i am executing 3rd line, below error is thrown by application
Caused by: java.lang.AbstractMethodError: com.inet.pool.b.getParameterMetaData()Ljava/sql/ParameterMetaData;
at com.core.admin.util.AnalyzeHelper.fillQuery(AnalyzeHelper.java:61)
is this due to subQuery issue?
how to resolve this?
use this for executing query
preStatement.executeQuery();
you need to have a result set for viewing
ResultSet rs=preStatement.executeQuery();
while(rs.next())
{
rs.getString(1);// I assume that first column is a String.If it is an INT then use rs.getInt(1);
//similarly for other columns
}
It may helps you.
qName = "select total_requests from (select 10000 as total_requests from dual)";
preStatement = connection.prepareStatement(qName);
ResultSet rs= preStatement.executeQuery();
I am preparing a SQL statement from values passed through a query string. ( I am using the Play! framework. Basically what I'm running into (not really an issue just something I don't like very much) is that when I want to use ? in the SQL string and set them later with dynamic values.
This is what I have:
String sql = "SELECT * FROM foobar_table WHERE";
if ( foo != 0 )
sql += " AND foo=?";
if ( !bar )
sql += " AND bar=?";
try{
PreparedStatement getStmt = con.prepareStatement(sql);
if ( foo != 0 )
getStmt.setInt(1,foo);
if ( foo != 0 && !bar )
getStmt.setBoolean(2, bar);
else
getStmt.setBoolean(1, bar);
} catch (SQLException e ){
e.printStackTrace();
}
This does work but as you can see not very intuitive. It's OK when there are 2 dynamic values but when you get up to 5 or 6 this would just get ridiculous.
Is there an easier way of doing this to make it more flexible so that I would know how to fill in all the ? in a better fashion?
An example (was too long for comment):
String sql = "SELECT * FROM foobar_table WHERE 1 = 1 ";
ArrayList paramList = new ArrayList();
if ( foo != 0 ) {
sql += " AND foo=?";
paramList.add(foo);
}
if ( !bar ) {
sql += " AND bar=?";
paramList.add(bar);
}
try{
PreparedStatement getStmt = con.prepareStatement(sql);
int index = 1;
for (Object param : paramList) {
getStmt.setObject(index, param);
index++;
}
// execute
} catch (SQLException e ){
e.printStackTrace();
}
Something like this maybe (just rough code but you get the idea):
class Param{
final int type;
final Object value;
Param(int type, Object value){
this.type = type;
this.value = value;
}
}
final List<Param> params = new ArrayList<>();
final StringBuilder sql = new StringBuilder("SELECT * FROM bcu_venue_events WHERE 1=1");
int foo = 0;
boolean bar = true;
if (foo != 0){
sql.append(" AND foo=?");
params.add(new Param(Types.INTEGER, foo));
}
if (!bar){
sql.append(" AND bar=?");
params.add(new Param(Types.BOOLEAN, bar));
}
try(Connection conn = null; PreparedStatement getStmt = conn.prepareStatement(sql.toString())) {
for(int i = 0; i < params.size(); i++){
Param p = params.get(i);
getStmt.setObject(i + 1, p.value, p.type);
}
} catch (SQLException e) {
e.printStackTrace();
}
How about this:
String sql = "SELECT * FROM foobar_table WHERE 1=1";
if ( foo != 0 )
sql += " AND foo=" + foo;
if ( !bar )
sql += " AND bar=" + bar;
try{
PreparedStatement getStmt = con.prepareStatement(sql);
} catch (SQLException e ){
e.printStackTrace();
}