15.10 - BLOB Data Type - Teradata Database

Represents a large binary string of raw bytes. A binary large object (BLOB) column can store binary objects, such as graphics, video clips, files, and documents.

where:

Syntax element …	Specifies …
n	the number of bytes to allocate for the BLOB column. The maximum number of bytes is 2097088000, which is the default if n is not specified.
K	that n is specified in kilobytes (KB). When K is specified, n cannot exceed 2047937.
M	that n is specified in megabytes (Mb). When M is specified, n cannot exceed 1999.
G	that n is specified in gigabytes (GB). When G is specified, n must be 1.
attribute	appropriate data type, column storage, or column constraint attributes. A BLOB column supports the following attributes: NOT NULL FORMAT TITLE For details on NOT NULL, see Chapter 11: “Default Value Control Phrases.” For details on FORMAT and TITLE, see Chapter 12: “Data Type Formats and Format Phrases.”

BLOB is ANSI SQL:2011 compliant.

The following table lists the client representations for the Teradata SQL BLOB data type.

Define the length of the BLOB string as k, where 0 <= k <= n.

Client CPU Architecture	Client Internal Data Format
IBM mainframe	Eight bytes (16-bit SMALLINT) length count k followed by k bytes of BYTE data.
UTS RISC Motorola 68000 WE 32000 Intel	Eight bytes (16-bit SMALLINT) length count k followed by k bytes of BYTE data.

A table can have a maximum of 32 LOB columns.

A LOB column cannot be a component of an index. Because of this restriction, a table must define at least one non-LOB column.

Queue tables cannot have BLOB columns.

The following are some functions and operators that support BLOB types:

BYTES

Concatenation operator (||)

SUBSTRING/SUBSTR

TYPE

Explicit data type conversion (CAST and Teradata conversion syntax)

User-defined functions (UDFs)

Stored procedures

External stored procedures

The following example creates a table that defines a BLOB column named blarge:

   CREATE TABLE t1

     (id INTEGER

     ,blarge BLOB(128K));

The following example shows a stored procedure that inserts part of a BLOB into one table and the remaining part of the BLOB into another table:

CREATE TABLE LocalData(ld_ID INTEGER, ld_DATA BLOB);

CREATE TABLE GlobalData (gd_ID INTEGER, gd_DATA BLOB);

CREATE PROCEDURE DataSplitter(IN local_ID  INTEGER, 

                              IN global_ID INTEGER,

                              IN all_DATA  BLOB)

BEGIN

   INSERT LocalData (local_ID, SUBSTRING(all_DATA FROM 1 FOR 128546));

   INSERT GlobalData (global_ID, SUBSTRING(all_DATA FROM 128547));

END;

FOR information on …	SEE …
functions and operators that support BLOB types	SQL Functions, Operators, Expressions, and Predicates.
implementing UDFs and external stored procedures that operate on BLOBs	SQL External Routine Programming.
implementing stored procedures that use BLOB local variables or parameters	“CREATE PROCEDURE” in SQL Data Definition Language. SQL Stored Procedures and Embedded SQL.