Develop Reference

find a name in a sqlite table and return the id?

What I'm trying to do seems simple but I get this error SQLITE_ERROR] SQL error or missing database (no such column: user1)
public String getIdUser(String name) {
try {
this.stat = conn.createStatement();
String sql = "SELECT id_user FROM User WHERE name = " + name;
ResultSet user = stat.executeQuery(sql);
return user.toString();
} catch (SQLException e) {
return null;
}
}

Replace
String sql = "SELECT FROM User WHERE name = " + name;
with
String sql = "SELECT * FROM User WHERE name = " + name; // you can also specify a column/columns instead of *

I see many problems in your code :
First
Your query should return something it should be :
SELECT col_name1, col_name2, ... FROM User ...
Or if you want to select every thing :
SELECT * FROM User ...
Second
String or Varchar should be between two quotes, your query for example should look like :
SELECT col_name1 FROM User WHERE name = 'name'
Third
I don't advice to use concatenation of query instead use Prepared Statement it is more secure and more helpful (I will provide an example)
Forth
To get a result you have to move the cursor you have to call result.next()
Fifth
Name of variable should be significant for example ResultSet should be ResultSet rs not ResultSet user
Your final code can be :
PrepareStatement prst = conn.prepareStatement("SELECT colName FROM User WHERE name = ?");
prst.setString(1, name);
ResultSet rs = prst.executeQuery();
if(rs.next()){
reuturn rs.getString("colName");
}

Without quoting the name string it's interpreted as column name, and thus the error you see. You could surround it with single quotes, but that's still generally a bad practice, and will leave the code vulnerable to SQL injection attacks.
Additionally, you're missing the select list (specifically, the id_user column), and missing getting it from the result set.
And finally, you forgot to close the statement and the result set.
If you put all of these corrections together, you should use something like this:
public String getIdUser(String name) {
try (PreparedStatmet ps =
conn.prepareStatement("SELECT id_user FROM User WHERE name = ?")) {
ps.setString(1, name);
try (ResultSet rs = stat.executeQuery()) {
if (rs.next()) {
return rs.getString(1);
}
}
} catch (SQLException ignore) {
}
return null;
}

Java JDBC, viewing the columns of the table that the user specifies

I am thinking about the design of the method that will enable the user to potentially pass a list of integers that indicate the columns that the user wishes to retrieve from the database.
I do not want to hardcode multiple methods that esentially do the same thing, i.e. show the user different columns but from the same table.
here is the code from Oracle tutorials on retrieving the values using JDBC:
public static void viewTable(Connection con, String dbName)
throws SQLException {
Statement stmt = null;
String query =
"select COF_NAME, SUP_ID, PRICE, " +
"SALES, TOTAL " +
"from " + dbName + ".COFFEES";
try {
stmt = con.createStatement();
ResultSet rs = stmt.executeQuery(query);
while (rs.next()) {
String coffeeName = rs.getString("COF_NAME");
int supplierID = rs.getInt("SUP_ID");
float price = rs.getFloat("PRICE");
int sales = rs.getInt("SALES");
int total = rs.getInt("TOTAL");
System.out.println(coffeeName + "\t" + supplierID +
"\t" + price + "\t" + sales +
"\t" + total);
}
} catch (SQLException e ) {
JDBCTutorialUtilities.printSQLException(e);
} finally {
if (stmt != null) { stmt.close(); }
}
}
So the query is not a problem, the column names can be concatenated, depending on which columns the user wants to see. The issue is in the try block. How does one .get the correct format from the result set? Or should I simply use the String for every column? Or should I hardcode all the table columns (rs.get depending on what data type the column is) and then in println return only the columns that the user wishes to see (actually how would I do that)? Well, I guess you understand my issue.

You can retrieve all the data from the particular table and use it to populate a collection of the appropriate object. And then based on the user's choice, you could just print out the appropriate columns.
Assuming you know how to create the collection of the appropriate object, I will explain how you can do the next step.
You can display a message to the user asking him to enter the columns he wishes to see. Like, Enter 1 to see the coffee name, 2 to see the supplier id, 3 to see the price etc. and 0 to view the data.
So you basically keep reading the int's until the user enters a 0. Once he enters a zero, display the requested values.

Batch Entry 0 insert into PGSQL-Call getNextException to see the cause

I am trying to find regular expression and if there are some duplicates, keep the unique ones and put the rest in a trash table.
but I get this Erro which I do not know what it is!
Here is my code:
public class RegexRemoverMain {
public static void main(String[] args) throws SQLException, ClassNotFoundException{
//Connection Parameters and Connect to Postgres Database
String data = "jdbc:postgresql://localhost:5432/postgres";
Class.forName("org.postgresql.Driver");
Connection conn = null;
//Connect to DB
conn = DriverManager.getConnection(
data, "username", "password");
//statements to get distinct owners
Statement ownerSt = conn.createStatement(
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_UPDATABLE);
//statement to get Image Ids of a user
Statement ownersImagesIdsSt = conn.createStatement(
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_UPDATABLE);
String insertSQL;
//an arraylist to store unique titles+tags reported by user
ArrayList<List<String>> result = new ArrayList<List<String>>();
//list for storing those Ids of a users which are filtered
List<String> filteredIds = new ArrayList<String>();
//list for storing those Ids of a users which are kept
List<String> ids = new ArrayList<String>();
//get the list of all the users
ResultSet distinctOwner = ownerSt.executeQuery("select distinct owner from \"flickrData_bulkUploadedFree\"");
distinctOwner.last();
distinctOwner.beforeFirst();
int count=0;
//RegularExpression Pattern
String theRegex= "((DSC)?(dsc)?(img)?(IMG)?(\\s?)(\\_?)((\\-?))[0-9]{1,9})";
Pattern checkRegex = Pattern.compile(theRegex);
//loop is going through all user's Images and check whether their the titles is one of the patterns if yes, check their title+description which are unique or not
//if yes, we keep them; if not; we throw them away or store in another place
while(distinctOwner.next()){
count = count++;
Statement insertSt = conn.createStatement(
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_UPDATABLE);
//store filtered images
String insertString = "INSERT INTO regexIamges"
+ "( id , owner, descriptio, title, tags) VALUES"
+ "(?,?,?,?,?)";
PreparedStatement preparedStatement = conn.prepareStatement(insertString);
//for each user exist in "flickrData_bulkUploadedFree"
String owner = distinctOwner.getString("owner");
ResultSet ownersImages;
ownersImages = ownersImagesIdsSt.executeQuery("select id, title, tags, descriptio from \"flickrData_bulkUploadedFree\" where owner = '" + owner +"';");
ownersImages.last();
ownersImages.beforeFirst();
//an list of images of a user's with the information about id, title, tags and descriptions in order to find unique Images
ArrayList<List<String>> bulkUploadList = new ArrayList<List<String>>();
while(ownersImages.next()){
String id = ownersImages.getString("id");
String title = ownersImages.getString("title");
String tags = ownersImages.getString("tags");
String description = ownersImages.getString("descriptio");
Matcher regexMatcher = checkRegex.matcher(title);
if (regexMatcher.find()){
if(regexMatcher.group().length() != 0){
List<String> rowsList = new ArrayList<String>();
rowsList.add(id);
rowsList.add(title);
rowsList.add(tags);
rowsList.add(description);
bulkUploadList.add(rowsList);
bulkUploadList.add(rowsList);
}
}
else{
insertSQL = "INSERT INTO \"regBulkfreeFlickrData\" SELECT * FROM \"flickrData_bulkUploadedFree\" where id ='"+id+"';";
insertSt.addBatch(insertSQL);
}
}
HashSet<String> hashSet = new HashSet<String>();
for(List<String> item : bulkUploadList) {
String title, tags, id, desc, uniqueString;
title = item.get(1);
tags = item.get(2);
id = item.get(0);
desc = item.get(3);
uniqueString = (tags + "#" + desc).trim().toUpperCase();
System.out.println(item);
if(!hashSet.contains(uniqueString)) {
result.add(item);
hashSet.add(uniqueString);
insertSQL = "INSERT INTO \"regBulkfreeFlickrData\" SELECT * FROM \"flickrData_bulkUploadedFree\" where id ='"+id+"';";
insertSt.addBatch(insertSQL);
} else {
// System.out.println("Filtered element " + uniqueString + "id " + id);
filteredIds.add(id);
preparedStatement.setString(1, id);
preparedStatement.setString(2, owner);
preparedStatement.setString(3, desc);
preparedStatement.setString(4, title);
preparedStatement.setString(5, tags);
preparedStatement.addBatch();
}
}
preparedStatement.executeBatch();
preparedStatement.close();
insertSt.executeBatch();
insertSt.close();
}
}
and the Error is this:
Exception in thread "main" java.sql.BatchUpdateException: Batch entry 0 INSERT INTO regexIamges( id , owner, descriptio, title, tags) VALUES('4292220054.0000000000000','23352125#N07','NoValue','IMG_2720','NoValue') was aborted. Call getNextException to see the cause.
at org.postgresql.jdbc2.AbstractJdbc2Statement$BatchResultHandler.handleError(AbstractJdbc2Statement.java:2743)
at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1928)
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:405)
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeBatch(AbstractJdbc2Statement.java:2892)
at uzh.textmining.RegexRemoverMain.main(RegexRemoverMain.java:116)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)
and the table is:
CREATE TABLE "RegexImages"
(id numeric,
owner character varying(254),
descriptio character varying(254),
title character varying(254),
tags character varying(254),
PRIMARY KEY (id)
)

thanks hasnae;
I used try catch and I got that the tableName in my code does not match the table Name in database.
another problem was the name of the table: I change all the letters to lower case to solve all the errors.

A problem that looks similar: https://stackoverflow.com/a/39227828/755804
(spoiler:
The total number of values, that is, the number of columns multiplied by the number of rows must not exceed 32767 for a single INSERT statement.
You can divide 32767 by the number of columns to get the maximal number of rows per one SQL INSERT statement.)

Oracle query execution error [duplicate]

I'm having an issue with my query not working. This is the command variable.
When it executes it should be retrieving the tuples that have BSc as their degree. I have tested this in oracle directly and the query returns these. It is identical to the command statement.
When I print out command, the line looks exactly the same as my command that worked in oracle.
SELECT distinct fname, lname, student_id FROM student where degree='BA';
Yet, it should be printing out to the screen. The tables are loaded into oracle already.
I've been racking my brain with this issue but can't seem to find a fix!
The error I keep getting is:
ORA-00911: invalid character
What I do is I store in degree the result from scanner which is a string. So concatenating it in the command variable shouldn't make an issue -- the query looks identical to what works in oracle.
Could it be because it wants a char instead of a string? If it does, then how would I get it to make "BSc" as a char? Concatenating chars sounds dumb.
Relevant code below:
private String getDegree() {
Scanner scan = new Scanner(System.in);
System.out.println("Please enter degree code (either BA or BSc)");
return scan.next();
}
//get the degree name
String degree = getDegree();
//get statement and execute appropriate select
Statement stmt = con.createStatement();
String command = "SELECT distinct fname, lname, student_id FROM student"+
" where degree='"+ degree + "';";
System.out.println(command);
ResultSet result = stmt.executeQuery(command);
//determine number of columns
ResultSetMetaData metadata = result.getMetaData();
int columns = metadata.getColumnCount();
//print heading
System.out.println("\nFNAME LNAME STUD_ID");
System.out.println("====================================");
//loop through result and print columns
while (result.next()){
for (int i=1; i <=columns; i++){
System.out.print(result.getString(i)+spaces(15-result.getString(i).length()));
}
System.out.println();
}
`

In JDBC your SQL statement should not be terminated by semicolon.
Change
String command = "SELECT distinct fname, lname, student_id FROM student"+
" where degree='"+ degree + "';";
to
String command = "SELECT distinct fname, lname, student_id FROM student"+
" where degree='"+ degree + "'";

Replace Parameters in SQL query text with XXXXX

I m writing a small utility that captures and logs SQL statements, but will have to remove sensitive data from the Query text and replace with with some dummy text (i.e:XXXXX).
What is a good way to parse the SQL query in java and replace parameters value?
for example:
replace
SELECT NAME, ADDRESS, .... FROM USER WHERE SSN IN ('11111111111111', '22222222222222');
with
SELECT NAME, ADDRESS, .... FROM USER WHERE SSN IN (?, ?);

Using JSQLParser (V0.8.9) this is a solution for your problem:
String sql ="SELECT NAME, ADDRESS, COL1 FROM USER WHERE SSN IN ('11111111111111', '22222222222222');";
Select select = (Select) CCJSqlParserUtil.parse(sql);
//Start of value modification
StringBuilder buffer = new StringBuilder();
ExpressionDeParser expressionDeParser = new ExpressionDeParser() {
#Override
public void visit(StringValue stringValue) {
this.getBuffer().append("XXXX");
}
};
SelectDeParser deparser = new SelectDeParser(expressionDeParser,buffer );
expressionDeParser.setSelectVisitor(deparser);
expressionDeParser.setBuffer(buffer);
select.getSelectBody().accept(deparser);
//End of value modification
System.out.println(buffer.toString());
//Result is: SELECT NAME, ADDRESS, COL1 FROM USER WHERE SSN IN (XXXX, XXXX)
This replaces all found String values within your SQL. To replace other types of data e.g. Long values, override the corresponding visit method in ExpressionDeParser.
Don't use regexp in this case. It turns out quickly to be hard maintainable.

The correct answer depends on how much you want to replace. Something like:
[0-9]{3}-?[0-9]{2}-?[0-9]{4}
will replace social security numbers pretty well. I always take regex code to
regexpal.com
to tweak it and work out bugs.
If you need to replace tons of sensitive information though, and if there are a lot of cases, definitely start looking into using a parser to parse the SQL query string. (such as jsqlparser, as Anirudh recommended.)

String sqlDebit = select * from table where and billing_cycle_start_date between :startDate and :endDate
java:
sqlDebit= sqlDebit.replaceAll(":startDate ", ""+startDate).replaceAll(":endDate", ""+endDate);

With prepare statement you can replace "?" in your query string with your value. Use number to specify which "?" you are referring too. They go by order from right to left.
For example: "SELECT LastName, FirstName FROM Person.Contact WHERE LastName = ? and FirstName = ?"
pstmt.setString(1, "LastNameValue");
pstmt.setString(2, "FirstNameValue");
see full example below:
public static void executeStatement(Connection con) {
try(PreparedStatement pstmt = con.prepareStatement("SELECT LastName, FirstName FROM Person.Contact WHERE LastName = ?");) {
pstmt.setString(1, "Smith");
ResultSet rs = pstmt.executeQuery();
while (rs.next()) {
System.out.println(rs.getString("LastName") + ", " + rs.getString("FirstName"));
}
}
// Handle any errors that may have occurred.
catch (SQLException e) {
e.printStackTrace();
}
}