Where are NULL Values in a LOB Column Stored?.When designing your table, consider the following design criteria: The ALTER DATABASE command will not work when there are CLOB or NCLOB columns in the tables. TO_LOB() function (see "LONG to LOB Migration Using the LONG-to-LOB API" in Chapter 10, "Internal Persistent LOBs").LONG-to-LOB API described in Chapter 8, "Migrating From LONGs to LOBs".Converting LONG Columns to LOBsĮxisting LONG columns can be converted to LOBs using either of the following methods: In Oracle9 i, you must convert LONG data types to LOBs and then replicate. Oracle simply omits columns containing these data types from replicated tables. Oracle does not support the replication of columns that use the LONG and LONG RAW data types. Replication in both local and distributed environments is not possible with a LONG or LONG RAW (see Oracle9i Replication) You can replicate LOBs in both local and distributed environments. Less flexibility in manipulating data in a random, piece-wise manner with LONG or LONG RAW data.LONGs must be accessed from the beginning to the desired location. There is greater flexibility in manipulating data in a random, piece-wise manner with LOBs. The valid accessible range is 1 to (2 32-1).īy contrast, a LONG or LONG RAW is limited to 2 gigabytes. The BFILE maximum is operating system dependent, but cannot exceed 4 gigabytes. When you access a LONG or LONG RAW, the entire value is returned.Ī LOB can be up to 4 gigabytes in size. When you access a LOB column, you can choose to fetch the locator or the data. In the case of a LONG or LONG RAW the entire value is stored in the table column. Only the LOB locator is stored in the table column BLOB and CLOB data can be stored in separate tablespaces and BFILE data is stored as an external file.įor inline LOBs, Oracle will store LOBs that are less than approximately 4,000 bytes of data in the table column. This is not possible with either a LONG or LONG RAW LOBs can be attributes of a user-defined datatype You can store only one LONG or LONG RAW in each row. You can store multiple LOBs in a single row Table 7-1 lists the similarities and differences between LOBs, LONGs, and LONG RAW types.
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