Issue: Oracle long type L; results: A summary of long types in Oracle

Summary of long types in Oracle

1, a Long data type is stored in a variable length string, the maximum length limit is 2GB.

2, for the text beyond a certain length, the basic can only be stored with a long type, the definition of many objects in the data dictionary is to be stored with a long.
1, a Long data type is stored in a variable length string, the maximum length limit is 2GB.

2, for the text beyond a certain length, the basic can only be stored with a long type, the definition of many objects in the data dictionary is to be stored with a long.

3, long type is mainly used to do not need to be a string search for a longer string of data, if you want to do character search will use VARCHAR2 type.

4. Many tools, including Sql*plus, are difficult to handle long data types.

5, LONG data type in use, to be limited to the size of the disk.

The ability to manipulate a LONG SQL statement:
1. SELECT statement

2. Set statement in UPDATE statement

3. The values statement in the INSERT statement

Limit:

1. A table can contain only one column of type LONG.

2. You cannot index a long type column.

3. A table containing a long column cannot be clustered.

4. You cannot insert the value of a long column into another table in Sql*plus, such as insert INTO ... select.

5. You cannot create a long type column in Sql*plus by querying other tables, such as CREATE table as SELECT.

6. A long column cannot be constrained (NULL, NOT NULL, except for default), such as: The key column (PRIMARY key) cannot be a long data type.

7. The Long type column cannot be used in the following clause of select: Where, group BY, order BY, and select statements with distinct.

8. A long column cannot be used for distribution queries.

Issue: Oracle long type L; results: A summary of long types in Oracle