I am building a REST-Interface for some Application and I use JPA and Hibernate to access a SQL-Database.
Now I am trying to check if a given nickname already exists.
I am doing it this way:
CriteriaBuilder builder = this.entityManager.getCriteriaBuilder();
CriteriaQuery<DBUser> query = builder.createQuery(DBUser.class);
Root<DBUser> from = query.from(DBUser.class);
Predicate uniqueNickname = builder.equal(from.get(DBUser_.nickName),newNickname);
query.select(from).where(uniqueNickname);
if (this.entityManager.createQuery(query).getResultList().size() == 0) {
//ok
} else {
//not ok
}
If I now have a User TEst in the database and newNickname="teST"
it puts the User TEst into the resultlist.
(I checked what the name in the resultlist is and it says TEst)
I am using the mysql connector "mysql-connector-java-6.0.6.jar".
Normally, CriteriaBuilder#equal is case-sensitive, you can achieve equals ignore case by comparing strings in uppercase variant:
Predicate uniqueNickname = builder.equal(builder.upper(from.<String>get(DBUser_.nickName)),
newNickname.toUpperCase());
In your case, the DB ignore the case sensitive completely.
Checking your MySQL DB and change the collation setting (the collation with _ci suffix is case-insensitve)
Related
I am trying to do an easy search on a table that can be on any kind of database. The following query is working an the most databases, but I cannot find a solution which works on mysql.
The tables in my database are generated by the active objects framework, so I cannot change the names or config of those instances.
Here is the query that works fine on all databases but MySQL:
select * from "AO_69D057_FILTER" where "SHARED" = true AND "CONTAINS_PROJECT" = true AND UPPER("FILTER_NAME") like UPPER('%pr%').
MySql is not able to use the table name in double quotes for some reason. If I use the unquoted table name it works on MySQL but not on Postgres. Postgres is converting the table name to lowercase because it is unquoted. AO is generating the table names in upper case.
I also tried to use an alias, but that can not work because of the evaluation hierarchy of the statement.
Any suggestions how to get rid of the table name problem?
By default double quotes are used to columns.
You can change it:
SET SQL_MODE=ANSI_QUOTES;
Here is the documentation about it:
http://dev.mysql.com/doc/refman/5.7/en/sql-mode.html
I had the same problem. I select the query according to the exception I get. In the first call of the db search, I try without quotes if it fails then I try with quotes. Then I set useQueryWithQuotes variable accordingly so that in future calls I do not need to check the exception. Below is the code snipped I am using.
private Boolean useQueryWithQuotes=null;
private final String queryWithQuotes = "\"OWNER\"=? or \"PRIVATE\"=?";
private final String queryWithoutQuotes = "OWNER=? or PRIVATE=?";
public Response getReports() {
List<ReportEntity> reports = null;
if(useQueryWithQuotes==null){
synchronized(this){
try {
reports = new ArrayList<ReportEntity>( Arrays.asList(ao.find(ReportEntity.class, Query.select().where(queryWithoutQuotes, getUserKey(), false))) );
useQueryWithQuotes = false;
} catch (net.java.ao.ActiveObjectsException e) {
log("exception:" + e);
log("trying query with quotes");
reports = new ArrayList<ReportEntity>( Arrays.asList(ao.find(ReportEntity.class, queryWithQuotes, getUserKey(), false)));
useQueryWithQuotes = true;
}
}
}else{
String query = useQueryWithQuotes ? queryWithQuotes : queryWithoutQuotes;
reports = new ArrayList<ReportEntity>( Arrays.asList(ao.find(ReportEntity.class, query, getUserKey(), false)));
}
...
}
The following JPA criteria query succeeds on Hibernate (4.2.7 final).
CriteriaBuilder criteriaBuilder=entityManager.getCriteriaBuilder();
CriteriaQuery<Boolean>criteriaQuery=criteriaBuilder.createQuery(Boolean.class);
Root<UserTable> root = criteriaQuery.from(entityManager.getMetamodel().entity(UserTable.class));
criteriaQuery.multiselect(root.get(UserTable_.enabled));
ParameterExpression<String>parameterExpression=criteriaBuilder.parameter(String.class);
criteriaQuery.where(criteriaBuilder.equal(criteriaBuilder.lower(criteriaBuilder.trim(root.get(UserTable_.emailId))), criteriaBuilder.lower(criteriaBuilder.trim(parameterExpression))));
List<Boolean> list = entityManager.createQuery(criteriaQuery).setParameter(parameterExpression, "admin").getResultList();
for(Boolean o:list)
{
System.out.println("enabled : "+o);
}
It is simply meant to return a scalar Boolean value from MySQL database. The corresponding column is of type TINYINT(1) in MySQL.
It generate the following SQL statement.
SELECT
usertable0_.enabled as col_0_0_
FROM
social_networking.user_table usertable0_
WHERE
lower(trim(BOTH FROM usertable0_.email_id))=lower(trim(BOTH FROM ?))
The same query fails on EclipseLink (2.5.1) in which case it returns nothing (no error, no exception). It however, generates a correct SQL statement as follows.
SELECT enabled
FROM projectdb.user_table
WHERE (LOWER(TRIM(email_id)) = LOWER(TRIM(?)))
bind => [admin]
The corresponding JPQL like so,
SELECT u.enabled
FROM UserTable u
WHERE lower(trim(u.emailId))=lower(trim(:emailId))
also doesn't get the value in question.
It however, works with additional columns as shown below.
CriteriaBuilder criteriaBuilder=entityManager.getCriteriaBuilder();
CriteriaQuery<Object[]>criteriaQuery=criteriaBuilder.createQuery(Object[].class);
Root<UserTable> root = criteriaQuery.from(entityManager.getMetamodel().entity(UserTable.class));
criteriaQuery.multiselect(root.get(UserTable_.enabled), root.get(UserTable_.firstName));
ParameterExpression<String>parameterExpression=criteriaBuilder.parameter(String.class);
criteriaQuery.where(criteriaBuilder.equal(criteriaBuilder.lower(criteriaBuilder.trim(root.get(UserTable_.emailId))), criteriaBuilder.lower(criteriaBuilder.trim(parameterExpression))));
List<Object[]> list = entityManager.createQuery(criteriaQuery).setParameter(parameterExpression, userName).getResultList();
One extra column root.get(UserTable_.firstName) is added and the return type of CriteriaQuery is changed from CriteriaQuery<Boolean> to CriteriaQuery<Object[]>.
The column is defined as follows in the corresponding entity.
#Basic(optional = false)
#NotNull
#Column(name = "enabled")
private Boolean enabled; //Getter and setter.
Why doesn't it given a Boolean value in EclipseLink?
This is due to EclipseLink bug https://bugs.eclipse.org/bugs/show_bug.cgi?id=340089 which causes EclipseLink to be unable to distinguish the value returned from the SQL query from the construct it uses internally to indicate there were no results. Selecting another value is the only workaround, but it seems simple enough that not many people hit it or just workaround it without commenting or voting for the bug.
I'm having troubles to save, get and compare a crypto hash from mysql DB.
As mentioned, i'm using 'crypto' module in order to generate hash (that hash includes special charachters).
My table is using "utf8_unicode_ci" collation.
Beacause of those special chars, I had troubles saving the hash to the DB.
So, I've tried to use this method:
exports.real_escape_string = function real_escape_string(str) {
return str.replace(/[\0\x08\x09\x1a\n\r"'\\\%]/g, function (char) {
switch (char) {
case "\0":
return "\\0";
case "\x08":
return "\\b";
case "\x09":
return "\\t";
case "\x1a":
return "\\z";
case "\n":
return "\\n";
case "\r":
return "\\r";
case "\"":
case "'":
case "\\":
case "%":
return "\\" + char; // prepends a backslash to backslash, percent,
// and double/single quotes
}
});
};
That worked and it did manage to save the hash to the DB, but for some reason when saving it to the DB it changes the hash itself.
I'm using the famous mysql module in order to access and perform actions on mysql database:
var mysql = require('mysql');
What else can I try ?
Use base64 when saving to the DB, and then decode when reading.
I have made a tiny software tool that allows me to display or run SQL generated from NHibernate. I made this because hbm2ddl.auto is not recommended for production.
I have one problem: when I generate the SQL I always get the infamous Index column unquoted, because I need .AsList() mappings. This prevents me to run the SQL.
In theory, if I had an XML configuration of NHibernate I could use hbm2ddl.keywords tag, but unfortunately since my tool is designed as a DBA-supporting tool for multiple environments, I must use a programmatic approach.
My approach (redundant) is the following:
private static Configuration BuildNHConfig(string connectionString, DbType dbType, out Dialect requiredDialect)
{
IPersistenceConfigurer persistenceConfigurer;
switch (dbType)
{
case DbType.MySQL:
{
persistenceConfigurer =
MySQLConfiguration
.Standard
.Dialect<MySQL5Dialect>()
.Driver<MySqlDataDriver>()
.FormatSql()
.ShowSql()
.ConnectionString(connectionString);
requiredDialect = new MySQL5Dialect();
break;
}
case DbType.MsSqlAzure:
{
persistenceConfigurer = MsSqlConfiguration.MsSql2008
.Dialect<MsSqlAzure2008Dialect>()
.Driver<SqlClientDriver>()
.FormatSql()
.ShowSql()
.ConnectionString(connectionString);
requiredDialect = new MsSqlAzure2008Dialect();
break;
}
default:
{
throw new NotImplementedException();
}
}
FluentConfiguration fc = Fluently.Configure()
.Database(persistenceConfigurer)
.ExposeConfiguration(
cfg => cfg.SetProperty("hbm2ddl.keywords", "keywords")
.SetProperty("hbm2ddl.auto", "none"))
.Mappings(
m => m.FluentMappings.AddFromAssemblyOf<NHibernateFactory>());
Configuration ret = fc.BuildConfiguration();
SchemaMetadataUpdater.QuoteTableAndColumns(ret);
return ret;
}
...
public static void GenerateSql(MainWindowViewModel viewModel)
{
Dialect requiredDialect;
Configuration cfg = BuildNHConfig(viewModel.ConnectionString, viewModel.DbType.Value, out requiredDialect);
StringBuilder sqlBuilder = new StringBuilder();
foreach (string sqlLine in cfg.GenerateSchemaCreationScript(requiredDialect))
sqlBuilder.AppendLine(sqlLine);
viewModel.Sql = sqlBuilder.ToString();
}
Explanation: when I want to set the ViewModel's SQL to display on a TextBox (yea, this is WPF) I initialize the configuration programmatically with connection string given in ViewModel and choose the dialect/provider accordingly. When I Fluently Configure NHibernate I both set hbm2ddl.keywords (tried both auto-quote and keywords, this being the default) and, following this blog post, I also use the SchemaMetadataUpdater.
The result is that I'm always presented with SQL like
create table `OrderHistoryEvent` (Id BIGINT NOT NULL AUTO_INCREMENT, EventType VARCHAR(255) not null, EventTime DATETIME not null, EntityType VARCHAR(255), Comments VARCHAR(255), Order_id VARCHAR(255), Index INTEGER, primary key (Id))
where the guilty Index column is not quoted.
The question is: given a programmatic and fluent configuration of NHibernate, how do I tell NHibernate to quote any reserved word in the SQL exported by GenerateSchemaCreationScript?
I have found a workaround: when I generate the update script (the one that runs with hbm2ddl.auto=update) the script is correctly quoted.
The infamous Index column has been already discussed and from my findings it's hardcoded in FNH (ToManyBase.cs, method public T AsList()).
Since the update script is a perfectly working creational script on an empty database, changing the code to generate an update script on an empty DB should equal generating a creational script.
This happens only because I want to generate the script on my own. There is probably a bug in NHibernate that only activates when you call GenerateSchemaCreationScript and not when you let your SessionFactory build the DB for you
Hi I have very big problem. I have a DetachedCriteria and I named it dc. I declared it this way DetachedCriteria dc = getDetachedCriteria(). I want to add a collation statement before the order by. The purpose of collation is to handle ñ. The statement I want to add is COLLATE utf8_spanish_ci. I did it this way dc.add(Restrictions.sqlRestriction(" COLLATE utf8_spanish_ci ")). Of course I got an error because this is wrong. I don't know to do it. Please help.
You can execute native SQL queries in order to take advantage of your particular database features, this is how is done in hibernate using detached criteria...
List<YourEntity> list = (List<YourEntity>) yourEntityDAO.getHibernateTemplate().execute(
new HibernateCallback() {
#Override
public Object doInHibernate(Session session) throws HibernateException {
SQLQuery sq = session.createSQLQuery("SELECT * FROM MY_TABLE");
return sq.addEntity(YourEntity.class).list();
}
});