Summary

In this chapter, you learned about the TO_DATE, TO_TIMESTAMP, and TO_CHAR conversion functions, with the available formats being highlighted. They can reference any elements and formats, with precision ranging from the day to fractions of a second. Century reference rules were described, including when the year is specified by just two digits and the century assignment can be calculated by the system.

You saw how the opposite of the TO_CHAR function is covered by the supplementary EXTRACT function, which can take only one element.

Finally, you learned about the reliability issues if date and time values are treated as a character string. From the visual perspective, the date and time values seem to be represented textually, right? However, that does not mean we should treat these values as strings, because they strongly depend on the format, which can be changed on the client and server sides anytime. Moreover, by migrating the solution to another server, different rules...