Date enquiry

Question

hello,
excuse my ignorance, but, can you insert a date stored as a string in a column with a "date" data type (ie, how can you insert a date entered by users in a jsp's textbox - say in '23/03/04' String format - in a table's column with a 'date' data type)? (I guess that, if possible, you would need to somehow convert it to YYYY-MM-DD format).
also, i would like to do this: i am having users to enter two dates in text boxes in a jsp (again in '23/04/04' format), and then i want to retrieve some numeric data from a table, for all dates between the first one and the day before the last one (in this table, i guess i need to use a 'date' data type for the dates, to be able to compare them; so, i would need to convert the dates entered as strings to 'Date' objects). Then, i need to check whether the retrieved numeric data, for each date, is equal or greater than a specific figure; if any of the retrieved numeric data is less than that specific figure, i need to return 'false' or something like that (ie, no further checking is necessary once a single retrieved numeric value is less than the required level). Any ideas?
Sorry, just thought about it, how can u convert a date in String format (say '23/04/04') to a 'Date' object?
thanks,

Answer 1

hello,
excuse my ignorance, but, can you insert a date
stored as a string in a column with a "date" data
type (ie, how can you insert a date entered by users
in a jsp's textbox - say in '23/03/04' String format
- in a table's column with a 'date' data type)? (I
guess that, if possible, you would need to somehow
convert it to YYYY-MM-DD format).
Databases store 'date'/'time'/'timestamp' as a timestamp. Or at least I have never seen a database that stored just a 'date' or a 'time'. This is true regardless of what the field is called.
So if you have a timestamp in your database you need to store a timestamp.
To do this the best way is to use the PreparedStatement method setTimestamp. You can also use setTime and setDate but if you do so you must understand that java and your database are still using timestamps and merely doing a close approximation to 'time' and 'date'.
To convert a string, from a gui (like JSP) to a java.util.Date you use java.text.SimpleDateFormat. You must then convert that to a java.sql.Timestamp (or Date/Time.)
also, i would like to do this: i am having users to
enter two dates in text boxes in a jsp (again in
'23/04/04' format), and then i want to retrieve some
numeric data from a table, for all dates between the
first one and the day before the last one (in this
table, i guess i need to use a 'date' data type for
the dates, to be able to compare them; so, i would
need to convert the dates entered as strings to
'Date' objects). Then, i need to check whether the
retrieved numeric data, for each date, is equal or
greater than a specific figure; if any of the
retrieved numeric data is less than that specific
figure, i need to return 'false' or something like
that (ie, no further checking is necessary once a
single retrieved numeric value is less than the
required level). Any ideas?Time range extraction must use exclusion on one end and inclusion on the other. A SQL string usuable in a prepared statement would look like this...
select afield from atable where aDateField > ? and aDateField <= ?
In the above the start date would 'bind' (using setTimestamp) to the first '?' and the end date would go to the second '?'.