Restrictions in Oracle

Restrictions in Oracle:

1. the maximum number of lists IN the IN clause is 1000. If the number is exceeded, an error is returned. You can use a temporary table to solve this problem;

2. The character length of the create trigger statement text cannot exceed 32 KB (the LONG and long raw types cannot be used in the TRIGGER. You can refer to the column value of the LOB type column in the TRIGGER, but cannot pass: NEW modifies data in the LOB column.) By the way, the PARENT keyword in the trigger is only valid in the nested table trigger,

3. Before 11g, DBMS_ SQL cannot exceed 32 K for the input SQL because the input parameter can only be of the VARCHAR2 type. After 11g, CLOB can be used as the input parameter. Therefore, this restriction is canceled.

4. the maximum size of a PL/SQL package, process, function, and trigger is 64 kB in UNIX, while that in WINDOWS is 32 KB (32 KB is not allowed, see the test below)

5. How long can an SQL statement be? (According to netizens) the ORACLE document is 64 KB. In fact, some tools may have lower limits than this value. However, it may take a long time to test it, even more than 1 MB (I tested K ). The specific length is 10 Gb, which is only related to a lot of environments: database configuration, disk space, memory capacity... in fact, I found in the PL/SQL test:

(In PL/SQL, the length of expressions/SQL itself can reach a relatively long length (50 K), such as: v_str: =: new. f1 |: ndw. f2... ; Select: new. f1 |: new. f2... Into v_str from dual; in addition, if you write: v_str: = 'A' | 'B' |... The allowed expression length is greatly reduced. If the expression/SQL is too long and exceeds the maximum program length allowed by an ORACLE package/procedure, a pls-123: program too large error is reported during compilation, this is caused by restrictions of the pl/SQL Compiler itself, that is, the length of the expression/SQL is limited by the maximum size of the package/process in PL/SQL)

Through the explanation in this article, we have a general understanding of the restrictions in Oracle databases. I hope you will pay special attention to the problems mentioned above in the subsequent Oracle database operations, to avoid unnecessary troubles for everyone's work.