[h2] Re: Bug alias for column in query

[Aleksey Konstantinov]

Checked with ALIAS_COLUMN_NAME option, really works. It is not clear why 
everything worked by default until 1.97 and now the behavior has changed.

вторник, 16 апреля 2019 г., 17:34:31 UTC+3 пользователь Aleksey 
Konstantinov написал:
>
> Hi Evgenij.
>
> This query is executed on the SQuirreL SQL Client (it uses h2 JDBC driver 
> version 199):
>
> [image: sqclient.jpg]
>
>
> четверг, 4 апреля 2019 г., 16:43:10 UTC+3 пользователь Evgenij Ryazanov 
> написал:
>>
>> Hello.
>>
>> How exactly do you read names of aliases? I cannot reproduce this issue 
>> in 1.4.197 and in other versions.
>>
>> try (Connection c = DriverManager.getConnection("jdbc:h2:mem:1")) 
>> {
>> Statement s = c.createStatement();
>> s.execute("CREATE TABLE test (ID int);");
>> s.execute("INSERT INTO test (ID) VALUES (1);");
>> try (ResultSet rs = s.executeQuery("SELECT ID AS VALUE_ID 
>> FROM test;")) {
>> System.out.println(rs.getMetaData().getColumnLabel(1));
>> while (rs.next()) {
>> System.out.println(rs.getInt("VALUE_ID"));
>> }
>> }
>> }
>>
>> VALUE_ID
>> 1
>>
>> It looks like you incorrectly use getColumnName(), this method returns ID 
>> as expected. JDBC drivers of many databases incorrectly return name of 
>> alias from this method too, but you should not expect that all databases 
>> will do the same.
>>
>> H2 can emulate such behavior, you need to use a compatibility mode 
>> or ALIAS_COLUMN_NAME setting.
>>
>

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[h2] Re: Bug alias for column in query

[Evgenij Ryazanov]

Hello.

How exactly do you read names of aliases? I cannot reproduce this issue in 
1.4.197 and in other versions.

try (Connection c = DriverManager.getConnection("jdbc:h2:mem:1")) {
Statement s = c.createStatement();
s.execute("CREATE TABLE test (ID int);");
s.execute("INSERT INTO test (ID) VALUES (1);");
try (ResultSet rs = s.executeQuery("SELECT ID AS VALUE_ID FROM 
test;")) {
System.out.println(rs.getMetaData().getColumnLabel(1));
while (rs.next()) {
System.out.println(rs.getInt("VALUE_ID"));
}
}
}

VALUE_ID
1

It looks like you incorrectly use getColumnName(), this method returns ID 
as expected. JDBC drivers of many databases incorrectly return name of 
alias from this method too, but you should not expect that all databases 
will do the same.

H2 can emulate such behavior, you need to use a compatibility mode 
or ALIAS_COLUMN_NAME setting.

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