The judgment of NULL value
$t {Type1id} = $ $pref {dbh}->selectrow_array ("Select Type1id from enq1 WHERE id =
3 ");
if ($t {type1id} = = 0) {
Print "Type1id is null\n";
}
==> is not a numeric term, this statement has a problem. Numeric items are private.
if (length ($t {type1id}) = = 0) {
Print "Type1id is null\n";
}
==> if NULL, this statement has a problem
If @rec contains null, the following action will have an error message
$t {Line1} = Join (", @rec);
($t {old1}, $t {new1p}, $t {new1q}) = $self->dbh->selectrow_array ("Select
Type1id,partsid,qty from enq1 WHERE id = $t {enq1_id} ");
91==> if ($t {old1} = = 0) {
--------------------------------------------------
[ERROR] [Client 127.0.0.1] Use the uninitialized value in numeric eq (=) at
./pro/mscenq1.pl line, <CONFIG> 11.,
--------------------------------------------------
How to determine if the value of an item is null (unresolved)
Fix It! First insert, put a constant (such as "B")
Origin ==>
637==> $t {NU1} = $self->dbh->selectrow_array ("Select Parts_unit from Parts_nu
where id = $t {Nuid1} ");
--------------------------------------------------
[Wed May 14 17:27:51 2008] [ERROR] [Client 127.0.0.1] Dbd::mysql::d b
Selectrow_array Failed:you have a error in your SQL syntax; Check the manual
That's corresponds to your MySQL server version for the right syntax to use near
"At line 1"/pro/mscenq1.pl line 637, <CONFIG> line, Referer:
--------------------------------------------------
To consider a situation where $T{NUID1} does not exist
Consider the situation of id=c
591==>
@{$t {p1}} = $self->dbh->selectrow_array ("select * from $t {ptable}")
WHERE id = $t {pid1} ");
--------------------------------------------------
[ERROR] [Client 127.0.0.1] Dbd::mysql::d b selectrow_array Failed:unknown
Column ' C ' WHERE clause ' at./pro/mscenq1.pl Line 591, <CONFIG> line 11.,
Referer
--------------------------------------------------
Consider the situation of $t{pid1}= ' C '
if ($#{$t {pid_list}} = = = 0 && $t {pid_list}[0] eq ' C ') {
Next
}
Copy a project's subroutine
Use strict;
Use DBI;
# Connect to the database
My (%t, $n, @fld, @rec, $pref);
Print "This is test3.pl.\n";
# Connect to the database
$ $pref {DSN} = "Dbi:mysql:host=localhost;database=cookbook";
$ $pref {DBH} = Dbi->connect ($ $pref {DSN}, "Cbuser", "Cbpass") or die "cannot"
Connect to server\n ";
$ $pref {dbh}->do ("SET NAMES UTF8");
if (!$ $pref {DBH}) {
Print "SQL read error!\n";
Exit
}
$ $pref {Table} = ' ENQ2 ';
$ $pref {oldid} = 4;
($pref) = Copy_one ($PREF);
# Close the database
$ $pref {dbh}->disconnect;
# Copy a project
Sub Copy_one {
My ($pref) = @_;
My (%t, @rec, $n);
# Take out the columns
$t {STH} = $ $pref {dbh}->prepare ("show COLUMNS from $ $pref {table}");
$t {sth}->execute;
while (@rec = $t {Sth}->fetchrow_array) {
Push (@{$t {columns}}, $rec [0]);
}
$t {sth}->finish;
# Fetching data (remember items that are NOT null)
@{$t {One}} = $ $pref {dbh}->selectrow_array ("SELECT * from $ $pref {table}")
WHERE id = $ $pref {oldid} ");
For $n (1. $#{$t {One}}) {
$t {Name} = $t {columns}[$n];
$t {Value} = $t {one}[$n];
if ($t {value}) {
$t {Value} = ' "'. $t {value}. '"';
Push (@{$t {names}}, $t {name});
Push (@{$t {values}}, $t {value});
}
}
$t {name1} = Join (', ', @{$t {names}});
$t {value1} = Join (', ', @{$t {values}});
# Insert New Item
$t {SQL} = ' INSERT into '. $ $pref {table}. '(';
$t {SQL}. = $t {name1}. ') VALUES (';
$t {SQL}. = $t {value1}. ')';
$t {do} = $ $pref {dbh}->do ($t {SQL});
# print ' do= $t {do}\n ';
return ($PREF);
}
# There may be a very simple command in MySQL to perform the above operation. The programs that have been done are here.
--------------------------------------------------------------------------------
MySQL Operation program Two
Return
--------------------------------------------------------------------------------
No ourref repeat operation.
$t {enq1_id} = $t {Q}->param ("enq1_id");
$t {Our1_new} = $self->dbh->selectrow_array ("Select Ourref from enq1 WHERE id = $t {enq1_id}");
# Get all existing QUO2 enq1id data, if there is the same not allowed to switch
# enq1 and Quo2 must be a pair of relationships
# Take out all the Ourref
$t {STH} = $self->dbh->prepare ("Select Enq1id from Quo2");
$t {sth}->execute;
while (@rec = $t {Sth}->fetchrow_array) {
$t {Our1} = $self->dbh->selectrow_array ("Select Ourref from enq1 WHERE id = $rec [0]");
Push (@{$t {Our1s}}, $t {our1});
}
$t {sth}->finish;
$t {Our1_old} = Join (', @{$t {Our1s}}});
if ($t {our1_old}!~/$t {our1_new}/) {
$t {SQL} = ' UPDATE quo2 SET enq1id = ';
$t {SQL}. = $t {enq1_id}. ' WHERE id = ';
$t {SQL}. = $t {quo2_id}. '"';
$t {do} = $self->dbh->do ("$t {SQL}");
}
Some actions to delete the contents of a table
Displays the contents of line No. 309 through 362 of the table Hull_no
Mysql> SELECT * from hull_no WHERE ID >= 309 and ID <= 362;
Delete Table Hull_no's No. 309 line to line 362 Hull_no
mysql> UPDATE hull_no SET hull_no = "" WHERE ID >= 309 and ID <= 362;
Query OK, rows affected (0.16 sec)
Rows matched:54 changed:54 warnings:0
Deletes the name of line No. 309 through 362 of the table Hull_no
mysql> UPDATE hull_no SET name = "" WHERE ID >= 309 and ID <= 362;
Query OK, rows affected (0.01 sec)
Rows matched:54 changed:54 warnings:0
Table deletes one row of actions
Mysql> show columns from Quo2;
+-----------+---------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+---------+------+-----+---------+----------------+
| ID | Int (11) | NO | PRI | NULL | auto_increment |
| Time | Date | YES | | NULL | |
| Enq1id | Int (11) | YES | | NULL | |
| originid | Int (11) | YES | | NULL | |
| Priceid | Int (11) | YES | | NULL | |
| Paymentid | Int (11) | YES | | NULL | |
| DELIVERY | Text | YES | | NULL | |
| percent0 | Int (11) | YES | | NULL | |
| Percent | Text | YES | | NULL | |
| Price | Text | YES | | NULL | |
| Total | Int (11) | YES | | NULL | |
| Memo | Text | YES | | NULL | |
+-----------+---------+------+-----+---------+----------------+
Rows in Set (0.08 sec)
mysql> ALTER TABLE Quo2 DROP enq1id;
Query OK, 6 rows affected (0.27 sec)
Records:6 duplicates:0 warnings:0
Mysql> show columns from Quo2;
+-----------+---------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+---------+------+-----+---------+----------------+
| ID | Int (11) | NO | PRI | NULL | auto_increment |
| Time | Date | YES | | NULL | |
| originid | Int (11) | YES | | NULL | |
| Priceid | Int (11) | YES | | NULL | |
| Paymentid | Int (11) | YES | | NULL | |
| DELIVERY | Text | YES | | NULL | |
| percent0 | Int (11) | YES | | NULL | |
| Percent | Text | YES | | NULL | |
| Price | Text | YES | | NULL | |
| Total | Int (11) | YES | | NULL | |
| Memo | Text | YES | | NULL | |
+-----------+---------+------+-----+---------+----------------+
Rows in Set (0.02 sec)
Mysql> show columns from Order1;
+-----------+---------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+---------+------+-----+---------+----------------+
| ID | Int (11) | NO | PRI | NULL | auto_increment |
| Time | Date | YES | | NULL | |
| OrderNo | Text | YES | | NULL | |
| originid | Int (11) | YES | | NULL | |
| Priceid | Int (11) | YES | | NULL | |
| Paymentid | Int (11) | YES | | NULL | |
| DELIVERY | Text | YES | | NULL | |
| Price | Text | YES | | NULL | |
| Total | Text | YES | | NULL | |
| Memo | Text | YES | | NULL | |
+-----------+---------+------+-----+---------+----------------+
Rows in Set (0.02 sec)
mysql> ALTER TABLE order1 DROP Price;
Query OK, rows affected (0.24 sec)
Records:10 duplicates:0 warnings:0
mysql> ALTER TABLE order1 DROP total;
Query OK, rows affected (0.17 sec)
Records:10 duplicates:0 warnings:0
Mysql> show columns from Order1;
+-----------+---------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+---------+------+-----+---------+----------------+
| ID | Int (11) | NO | PRI | NULL | auto_increment |
| Time | Date | YES | | NULL | |
| OrderNo | Text | YES | | NULL | |
| originid | Int (11) | YES | | NULL | |
| Priceid | Int (11) | YES | | NULL | |
| Paymentid | Int (11) | YES | | NULL | |
| DELIVERY | Text | YES | | NULL | |
| Memo | Text | YES | | NULL | |
+-----------+---------+------+-----+---------+----------------+
8 rows in Set (0.01 sec)
Table adds one line of action
Mysql> show columns from ENQ2;
+-----------+---------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+---------+------+-----+---------+----------------+
| ID | Int (11) | NO | PRI | NULL | auto_increment |
| Time | Date | YES | | NULL | |
| Enq1id | Int (11) | YES | | NULL | |
| originid | Int (11) | YES | | NULL | |
| Priceid | Int (11) | YES | | NULL | |
| Paymentid | Int (11) | YES | | NULL | |
| Makerid | Int (11) | YES | | NULL | |
| DELIVERY | Text | YES | | NULL | |
| Type1id | Text | YES | | NULL | |
| Partsid | Text | YES | | NULL | |
| QTY | Text | YES | | NULL | |
| Memo | Text | YES | | NULL | |
+-----------+---------+------+-----+---------+----------------+
Rows in Set (0.06 sec)
mysql> ALTER TABLE enq2 ADD LanguageID INT after Enq1id;
Query OK, 1 row affected (0.45 sec)
Records:1 duplicates:0 warnings:0
Mysql> show columns from ENQ2;
+------------+---------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------+---------+------+-----+---------+----------------+
| ID | Int (11) | NO | PRI | NULL | auto_increment |
| Time | Date | YES | | NULL | |
| Enq1id | Int (11) | YES | | NULL | |
| LanguageID | Int (11) | YES | | NULL | |
| originid | Int (11) | YES | | NULL | |
| Priceid | Int (11) | YES | | NULL | |
| Paymentid | Int (11) | YES | | NULL | |
| Makerid | Int (11) | YES | | NULL | |
| DELIVERY | Text | YES | | NULL | |
| Type1id | Text | YES | | NULL | |
| Partsid | Text | YES | | NULL | |
| QTY | Text | YES | | NULL | |
| Memo | Text | YES | | NULL | |
+------------+---------+------+-----+---------+----------------+
Rows in Set (0.00 sec)
Mysql> show columns from Quo1;
+----------+---------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+---------+------+-----+---------+----------------+
| ID | Int (11) | NO | PRI | NULL | auto_increment |
| Time | Date | YES | | NULL | |
| Enq2id | Int (11) | YES | | NULL | |
| Makerref | Text | YES | | NULL | |
| Memo | Text | YES | | NULL | |
+----------+---------+------+-----+---------+----------------+
5 rows in Set (0.30 sec)
mysql> ALTER TABLE quo1 ADD price TEXT after Makerref;
Query OK, 2 rows affected (0.67 sec)
Records:2 duplicates:0 warnings:0
Mysql> show columns from Quo1;
+----------+---------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+---------+------+-----+---------+----------------+
| ID | Int (11) | NO | PRI | NULL | auto_increment |
| Time | Date | YES | | NULL | |
| Enq2id | Int (11) | YES | | NULL | |
| Makerref | Text | YES | | NULL | |
| Price | Text | YES | | NULL | |
| Memo | Text | YES | | NULL | |
+----------+---------+------+-----+---------+----------------+
6 rows in Set (0.02 sec)
Modify the operation of a column (rename and change data definition)
Mysql> show columns from Order1;
+-----------+---------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+---------+------+-----+---------+----------------+
| ID | Int (11) | NO | PRI | NULL | auto_increment |
| Time | Date | YES | | NULL | |
| Quo2id | Int (11) | YES | | NULL | |
| originid | Int (11) | YES | | NULL | |
| Priceid | Int (11) | YES | | NULL | |
| Paymentid | Int (11) | YES | | NULL | |
| DELIVERY | Text | YES | | NULL | |
| Price | Text | YES | | NULL | |
| Total | Text | YES | | NULL | |
| Memo | Text | YES | | NULL | |
+-----------+---------+------+-----+---------+----------------+
Rows in Set (0.16 sec)
mysql> ALTER TABLE order1 change quo2id orderno TEXT;
Query OK, 6 rows affected (0.56 sec)
Records:6 duplicates:0 warnings:0
Mysql> show columns from Order1;
+-----------+---------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+---------+------+-----+---------+----------------+
| ID | Int (11) | NO | PRI | NULL | auto_increment |
| Time | Date | YES | | NULL | |
| OrderNo | Text | YES | | NULL | |
| originid | Int (11) | YES | | NULL | |
| Priceid | Int (11) | YES | | NULL | |
| Paymentid | Int (11) | YES | | NULL | |
| DELIVERY | Text | YES | | NULL | |
| Price | Text | YES | | NULL | |
| Total | Text | YES | | NULL | |
| Memo | Text | YES | | NULL | |
+-----------+---------+------+-----+---------+----------------+
Rows in Set (0.02 sec)
Current 1/4 page
1234 Next read the full text
