What exactly do quotation marks around the table name do?
Solution 1:
Putting double-quotes around an identifier in Oracle causes Oracle to treat the identifier as case sensitive rather than using the default of case-insensitivity. If you create a table (or a column) with double-quotes around the name, you must always refer to the identifier with double quotes and by correctly specifying the case (with the exception of all upper case identifiers, where double-quotes are meaningless).
Under the covers, Oracle is always doing case-sensitive identifier matching. But it always casts identifiers that are not double-quoted to upper case before doing the matching. If you put double-quotes around an identifier, Oracle skips the casting to upper case.
So if you do something like
CREATE TABLE my_table(
col1 number,
col2 number
)
you can
SELECT * FROM my_table
SELECT * FROM MY_TABLE
SELECT * FROM My_Table
SELECT * FROM "MY_TABLE"
but something like
SELECT * FROM "my_table"
will fail.
On the other hand, if you do something like
CREATE TABLE "my_other_table"(
col1 number,
col2 number
)
you cannot do
SELECT * FROM my_other_table
SELECT * FROM MY_OTHER_TABLE
SELECT * FROM My_Other_Table
SELECT * FROM "MY_OTHER_TABLE"
but this
SELECT * FROM "my_other_table"
will work
Solution 2:
It should be added that identifiers in quotation marks may contain special characters, e.g. "a-b c.d" is a valid identifier.