A BLOB
is a binary large object that can hold a variable amount of data. The four BLOB
types are TINYBLOB
, BLOB
, MEDIUMBLOB
, and LONGBLOB
. These differ only in the maximum length of the values they can hold. The four TEXT
types are TINYTEXT
, TEXT
, MEDIUMTEXT
, and LONGTEXT
. These 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.
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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 5.1.10, '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.
- AutoMounter is a sandboxed app, so we don't have access to any part of your filesystem, except for a secure 'sandboxed' folder inside your user's Library folder. With AutoMounter 1.5 we introduced a Pro Settings in-app purchase where you can choose where you'd like to mount your shares - even in /Volumes!
- Windows Management Framework (WMF) 5.1 brings functionality that has been updated from WMF 5.0. WMF 5.1 is available for installation only on Windows Server 2012 R2, Windows Server 2012, Windows 2008 R2 SP1, Windows 8.1, and Windows 7 SP1. Some of the new and updated features in this release include: Constrained file copying to/from JEA endpoints.
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 will 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
andTEXT
columns, you must specify an index prefix length. ForCHAR
andVARCHAR
, a prefix length is optional. See Section 8.3.4, 'Column Indexes'.BLOB
andTEXT
columns cannot haveDEFAULT
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 ofmax_sort_length
is 1024. You can make more bytes significant in sorting or grouping by increasing the value ofmax_sort_length
at server startup or runtime. Any client can change the value of its sessionmax_sort_length
variable:Instances of
BLOB
orTEXT
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 theMEMORY
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 includeBLOB
orTEXT
columns in the query result only if they are really needed. For example, avoid usingSELECT *
, which selects all columns.The maximum size of a
BLOB
orTEXT
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 size of the communications buffers. You can change the message buffer size by changing the value of themax_allowed_packet
variable, but you must do so for both the server and your client program. For example, both mysql and mysqldump enable you to change the client-sidemax_allowed_packet
value. See Section 5.1.1, 'Configuring the Server', Section 4.5.1, 'mysql — The MySQL Command-Line Client', and Section 4.5.4, 'mysqldump — A Database Backup Program'. You may also want to compare the packet sizes and the size of the data objects you are storing with the storage requirements, see Section 11.7, 'Data Type Storage Requirements'
Each BLOB
or TEXT
value is represented internally by a separately allocated object. This is in contrast to all other data types, for which storage is allocated once per column when the table is opened.
In some cases, it may be desirable to store binary data such as media files in BLOB
or TEXT
columns. You may find MySQL's string handling functions useful for working with such data. See Section 12.8, 'String Functions and Operators'. For security and other reasons, it is usually preferable to do so using application code rather than giving application users the FILE
privilege. You can discuss specifics for various languages and platforms in the MySQL Forums (http://forums.mysql.com/).
To find a missing number in a Sequence, first we must have a Rule
Sequence
A Sequence is a set of things (usually numbers) that are in order.
Each number in the sequence is called a term (or sometimes 'element' or 'member'), read Sequences and Series for a more in-depth discussion.
Finding Missing Numbers
To find a missing number, first find a Rule behind the Sequence.
Sometimes we can just look at the numbers and see a pattern:
Example: 1, 4, 9, 16, ?
Mac os x mountain lion apple store. Answer: they are Squares (12=1, 22=4, 32=9, 42=16, .)
Rule: xn = n2
Sequence: 1, 4, 9, 16, 25, 36, 49, .
Did you see how we wrote that rule using 'x' and 'n' ?
xn means 'term number n', so term 3 is written x3
And we can calculate term 3 using: Waltr 2 6 2016.
x3 = 32 = 9
We can use a Rule to find any term. For example, the 25th term can be found by 'plugging in' 25 wherever n is.
x25 = 252 = 625
How about another example:
Example: 3, 5, 8, 13, 21, ?
After 3 and 5 all the rest are the sum of the two numbers before,
Apple recovery key 2019. Cardhop 1 1 1 – manage your contacts info. That is 3 + 5 = 8, 5 + 8 = 13 etc, which is part of the Fibonacci Sequence:
3, 5, 8, 13, 21, 34, 55, 89, .
Which has this Rule:
Rule: xn = xn-1 + xn-2
Now what does xn-1 mean? It means 'the previous term' as term number n-1 is 1 less than term number n.
And xn-2 means the term before that one.
Let's try that Rule for the 6th term:
x6 = x6-1 + x6-2
x6 = x5 + x4
So term 6 equals term 5 plus term 4. We already know term 5 is 21 and term 4 is 13, so:
x6 = 21 + 13 = 34
Many Rules
One of the troubles with finding 'the next number' in a sequence is that mathematics is so powerful we can find more than one Rule that works.
What is the next number in the sequence 1, 2, 4, 7, ?
Here are three solutions (there can be more!):
Solution 1: Add 1, then add 2, 3, 4, .
So, 1+1=2, 2+2=4, 4+3=7, 7+4=11, etc.
Rule: xn = n(n-1)/2 + 1
Sequence: 1, 2, 4, 7, 11, 16, 22, .
(That rule looks a bit complicated, but it works)
Solution 2: After 1 and 2, add the two previous numbers, plus 1:
Rule: xn = xn-1 + xn-2 + 1
Sequence: 1, 2, 4, 7, 12, 20, 33, .
Solution 3: After 1, 2 and 4, add the three previous numbers
Rule: xn = xn-1 + xn-2 + xn-3
Sequence: 1, 2, 4, 7, 13, 24, 44, .
So, we have three perfectly reasonable solutions, and they create totally different sequences.
Which is right? They are all right.
And there are other solutions .. it may be a list of the winners' numbers . so the next number could be . anything! |
Simplest Rule
When in doubt choose the simplest rule that makes sense, but also mention that there are other solutions.
Finding Differences
Sometimes it helps to find the differences between each pair of numbers . this can often reveal an underlying pattern.
Here is a simple case:
This war of mine 1 2 7. The differences are always 2, so we can guess that '2n' is part of the answer.
Let us try 2n:
The last row shows that we are always wrong by 5, so just add 5 and we are done:
Rule: xn = 2n + 5
OK, we could have worked out '2n+5' by just playing around with the numbers a bit, but we want a systematic way to do it, for when the sequences get more complicated.
Second Differences
In the sequence {1, 2, 4, 7, 11, 16, 22, .} we need to find the differences .
. and then find the differences of those (called second differences), like this:
The second differences in this case are 1.
With second differences we multiply by n22
In our case the difference is 1, so let us try just n22:
n: | 1 | 2 | 3 | 4 | 5 |
---|---|---|---|---|---|
Terms (xn): | 1 | 2 | 4 | 7 | 11 |
n22: | 0.5 | 2 | 4.5 | 8 | 12.5 |
Wrong by: | 0.5 | 0 | -0.5 | -1 | -1.5 |
We are close, but seem to be drifting by 0.5, so let us try: n22 − n2
Wrong by 1 now, so let us add 1:
n22 − n2 + 1 | 1 | 2 | 4 | 7 | 11 |
---|---|---|---|---|---|
Wrong by: | 0 | 0 | 0 | 0 | 0 |
We did it!
The formula n22 − n2 + 1 can be simplified to n(n-1)/2 + 1
So by 'trial-and-error' we discovered a rule that works:
Rule: xn = n(n-1)/2 + 1
Sequence: 1, 2, 4, 7, 11, 16, 22, 29, 37, .
Other Types of Sequences
Read Sequences and Series to learn about:
Automounter 1 5 7 Esv
And there are also:
And many more!
Automounter 1 5 75
In truth there are too many types of sequences to mention here, but if there is a special one you would like me to add just let me know.