The BLOB and TEXT Types correspond to the four  BLOB  types and have the same maximum lengths and storage requirements. See Section 11.7, “Data Type Storage Requirements” . BLOB  values are treated as binary strings (byte strings). They have the  binary  character set and collation, and comparison and sorting are based on the numeric values of the bytes in column values.  TEXT  values are treated as nonbinary strings (character strings). They have a character set other than  binary , and values are sorted and compared based on the collation of the character set. If strict SQL mode is not enabled and you assign a value to a  BLOB  or  TEXT  column that exceeds the column’s maximum length, the value is truncated to fit and a warning is generated. For truncation of nonspace characters, you can cause an error to occur (rather than a warning) and suppress insertion of the value by using strict SQL mode. See Section 5.1.11, “Server SQL Modes” . Truncation of excess trailing spaces from values to be inserted into  TEXT  columns always generates a warning, regardless of the SQL mode. For  TEXT  and  BLOB  columns, there is no padding on insert and no bytes are stripped on select. If a  TEXT  column is indexed, index entry comparisons are space-padded at the end. This means that, if the index requires unique values, duplicate-key errors occur for values that differ only in the number of trailing spaces. For example, if a table contains  ’a’ , an attempt to store  ’a ’  causes a duplicate-key error. This is not true for  BLOB  columns. In most respects, you can regard a  BLOB  column as a  VARBINARY  column that can be as large as you like. Similarly, you can regard a  TEXT  column as a  VARCHAR  column.  BLOB  and  TEXT  differ from  VARBINARY and  VARCHAR  in the following ways: •For indexes on  BLOB  and  TEXT  columns, you must specify an index prefix length. For  CHAR  and VARCHAR , a prefix length is optional. See Section 8.3.5, “Column Indexes” . • BLOB  and  TEXT  columns cannot have  DEFAULT  values. If you use the  BINARY  attribute with a  TEXT  data type, the column is assigned the binary ( _bin ) collation of the column character set. LONG  and  LONG VARCHAR  map to the  MEDIUMTEXT  data type. This is a compatibility feature. MySQL Connector/ODBC defines  BLOB  values as  LONGVARBINARY  and  TEXT  values as  LONGVARCHAR . Because  BLOB  and  TEXT  values can be extremely long, you might encounter some constraints in using them: •Only the first  max_sort_length  bytes of the column are used when sorting. The default value of max_sort_length  is 1024. You can make more bytes significant in sorting or grouping by increasing the value of  max_sort_length  at server startup or runtime. Any client can change the value of its session  max_sort_length  variable: mysql>  SET max_sort_length = 2000; mysql>  SELECT id, comment FROM t ->  ORDER BY comment; •Instances of  BLOB  or  TEXT  columns in the result of a query that is processed using a temporary table causes the server to use a table on disk rather than in memory because the  MEMORY  storage engine does not support those data types (see Section 8.4.4, “Internal Temporary Table Use in MySQL” ). Use of disk incurs a performance penalty, so include  BLOB  or  TEXT  columns in the query result only if they are really needed. For example, avoid using  SELECT * , which selects all columns. •The maximum size of a  BLOB  or  TEXT  object is determined by its type, but the largest value you actually can transmit between the client and server is determined by the amount of available memory and the 2042