i'm new to sql and pl/sql. To practice I was giving an assignment to make a calculator. That part works. But they also want the possibility to type the calculation in the text field and then it needs to work. For example 4+4 (then the = button or enter on your keyboard) or 4+6-3=.
My calculator with buttons works, but not if I type a calculation in the text field. Can anyone help me with this?
This is the code I have in my total:
declare
l_operator varchar2(1) := :P3_OPERATOR;
l_value1 number := :P3_VALUE1;
l_value2 number := :P3_VALUE2;
l_result number := nvl(:P3_VALUE1,0);
begin
case l_operator
when '+' then
l_result := l_value1 + l_value2;
when '-' then
l_result := l_value1 - l_value2;
when '*' then
l_result := l_value1 * l_value2;
when '/' then
l_result := l_value1 / l_value2;
else
null;
end case;
:P3_OPERATOR := null;
:P3_VALUE2 := null;
:P3_VALUE1 := l_result;
:P3_NUMBERFIELD := l_result;
end;
with this for als extra for the +, -, * and \ .
:P12_OPERATOR := '*';
:P12_NUMBERFIELD := :P12_OPERATOR;
and this is the code for all my number buttons:
begin
if :P12_OPERATOR is null then
:P12_VALUE1 := :P12_VALUE1 || 4;
:P12_NUMBERFIELD := :P12_VALUE1;
elsif :P12_OPERATOR is not null then
:P12_VALUE2 := :P12_VALUE2 || 4;
:P12_NUMBERFIELD := :P12_VALUE2;
end if;
end;
This is not a typical way to use SQL or PL/SQL (or APEX which it looks like you are also using)!
You could evaluate any expression typed in with code like this:
begin
execute immediate 'select ' || :P3_NUMBERFIELD || ' from dual' into l_result;
exception
when others then
l_result := 'Invalid input';
end;
The exception part is to stop the calculator going wrong if the user types in nonsense like "hello world" instead of an arithmetic expression. The user would need to type in an expression like 4+4 without typing the equals sign, and then press a button to invoke the process to calculate the result.
Related
create or replace trigger emp_trig
before insert or update of salary on emp
for each row
when `REGEXP_LIKE(:new.job_id, 'ac*','i')` -- Here
BEGIN
IF inserting then
:new.commission_pct := 0.20;
elsif (:old.commission_pct is null) then
:new.commission_pct := 0.1;
END IF;
END;
create or replace trigger emp_trig
before insert or update of salary on emp
for each row
when (REGEXP_LIKE(new.job_id, 'ac*','i'))
BEGIN
IF inserting then
:new.commission_pct := 0.20;
elsif (:old.commission_pct is null) then
:new.commission_pct := 0.1;
END IF;
END;
/
Hey. if you are trying to do a simple match then avoid using Regular
expression. Instead go with LIKE and your test condition. Below
snippet illustrates a simple example to suffice your requirement. Hope
it helps
CREATE OR REPLACE TRIGGER emp_trig before
INSERT OR
UPDATE OF sal ON emp FOR EACH row
WHEN (new.job LIKE '%TEST%')
DECLARE
BEGIN
IF inserting THEN
:new.comm := 0.20;
elsif (:old.comm IS NULL) THEN
:new.comm := 0.1;
END IF;
END;
I'm working on a tool that imports textfiles into a BLOB column (OracleDB). This is handled via an Apex page with a File Browse button and connected import procedure.
For more details about the import to BLOB procedure: http://ittichaicham.com/2011/03/file-browser-in-apex-4-with-blob-column-specified-in-item-source-attribute/
The textfiles that I'm using contain special characters, null values, decimal seperators etc. For example:
(...) 111888|Overflakkée, Blabla|streetname with Rhône||12-13|UXC
Placename (...)
Since it's all character data, I'm converting the BLOB to CLOB with this procedure:
FUNCTION blob_to_clob (blob_in IN BLOB)
RETURN CLOB
AS
v_clob CLOB;
v_varchar VARCHAR2(32767);
v_start PLS_INTEGER := 1;
v_buffer PLS_INTEGER := 32767;
BEGIN
DBMS_LOB.CREATETEMPORARY(v_clob, TRUE);
FOR i IN 1..CEIL(DBMS_LOB.GETLENGTH(blob_in) / v_buffer)
LOOP
v_varchar := UTL_RAW.CAST_TO_VARCHAR2(DBMS_LOB.SUBSTR(blob_in, v_buffer, v_start));
DBMS_LOB.WRITEAPPEND(v_clob, LENGTH(v_varchar), v_varchar);
v_start := v_start + v_buffer;
END LOOP;
RETURN v_clob;
END blob_to_clob;
See for more info:http://www.dba-oracle.com/t_convert_blob_to_clob_script.htm
The problem:
While converting the blob to clob, some of the special characters are lost/altered.
For example, this row:
(...) 111888|Overflakkée, Blabla|streetname with Rhône||12-13|UXC
Placename (...)
will become this row:
(...) 111888|Overflakk� Blabla|streetname with Rh�|12-13|UXC
Placename (...)
Row length, characters and even seperators (in this case a '|') are altered/not visible.
Is there a way to obtain the lost characters + keep seperators/null values in place? (if its necessary to change 'é' to 'e', that's fine).
Is there a more efficient way to import textfiles into a BLOB/CLOB column?
Regards
You need to do a conversion from the source character set to the character set of the database
Here is an example I made (mainly for getting big json objects, javascript is utf8, to work with in a 8859p1 database), It's pretty simple so I won't explain it too much.
example usage with conversion:
l_clob := blob_to_clob (l_blob, '1');
Function:
function blob_to_clob (blob_in in blob, p_convertutf8 in char default 0)
return clob as
/* Ólafur Tryggvason */
l_clob clob;
l_varchar varchar2 (32767);
l_start pls_integer := 1;
l_buffer pls_integer := 32767;
l_characterset nls_database_parameters.value%type;
begin
select value
into l_characterset
from nls_database_parameters
where parameter = 'NLS_CHARACTERSET';
dbms_lob.createtemporary (l_clob, true);
for i in 1 .. ceil (dbms_lob.getlength (blob_in) / l_buffer) loop
l_varchar := utl_raw.cast_to_varchar2 (dbms_lob.substr (blob_in, l_buffer, l_start));
if p_convertutf8 = '1' then
l_varchar := convert (l_varchar, l_characterset, 'UTF8'); -- WE8ISO8859P1
end if;
dbms_lob.writeappend (l_clob, length (l_varchar), l_varchar);
l_start := l_start + l_buffer;
end loop;
return l_clob;
end blob_to_clob;
Update
As Graymatter has observed, regex fails to match when there are at least 2 extra line breaks before the second target. That is to say, changing the concatenation loop to "for I := 0 to 1" will make the regex-match fail.
As shown in the code below, without the concatenation, the program can get the two values using regex. However, with the concatenation, the program cannot get the two values.
Could you help to comment on the reason and the workaround ?
program Project1;
{$APPTYPE CONSOLE}
uses
// www.regular-expressions.info/delphi.html
// http://www.regular-expressions.info/download/TPerlRegEx.zip
PerlRegEx,
SysUtils;
procedure Test;
var
Content: UTF8String;
Regex: TPerlRegEx;
GroupIndex: Integer;
I: Integer;
begin
Regex := TPerlRegEx.Create;
Regex.Regex := 'Value1 =\s*(?P<Value1>\d+)\s*.*\s*Value2 =\s*(?P<Value2>\d*\.\d*)';
Content := '';
for I := 0 to 10000000 do
begin
// Uncomment here to see effect
// Content := Content + 'junkjunkjunkjunkjunk' + sLineBreak;
end;
Regex.Subject := 'junkjunkjunkjunkjunk' +
sLineBreak + ' Value1 = 1' +
sLineBreak + 'junkjunkjunkjunkjunk' + Content +
sLineBreak + ' Value2 = 1.23456789' +
sLineBreak + 'junkjunkjunkjunkjunk';
if Regex.Match then
begin
GroupIndex := Regex.NamedGroup('Value1');
Writeln(Regex.Groups[GroupIndex]);
GroupIndex := Regex.NamedGroup('Value2');
Writeln(Regex.Groups[GroupIndex]);
end
else
begin
Writeln('No match');
end;
Regex.Free;
end;
begin
Test;
Readln;
end.
Adding this line works.
Regex.Options := [preSingleLine];
From the documentation:
preSingleLine
Normally, dot (.) matches anything but a newline (\n). With preSingleLine, dot (.) will match anything, including newlines. This allows a multiline string to be regarded as a single entity. Equivalent to Perl's /s modifier. Note that preMultiLine and preSingleLine can be used together.
When there is only one line break before the second target, the regex can match even without preSingleline. The reason is because \s can match line return.
I have quite a number of text fields I need to deal with. In order to process them the first thing I need to do is to normalize the set of characters I deal with. I need my output string to contain the following;
A-Z, 0-9 and space and I want all lower case converted to upper case.
So I use the following in pl/sql;
X := UPPER(TRIM(REGEXP_REPLACE
(REGEXP_REPLACE(X, '[^0-9A-Za-z ]', ' '),'( )* ',' ')));
This is rather slow. What would be faster?
You can try this approach, which looks to be much faster based on some (very) loose tests. Its a function that's compiled natively:
CREATE OR REPLACE function clean_string(
in_string in varchar2)
return varchar2 AS
out_string varchar2(4000) := '';
in_length number;
cnt number := 0;
in_char char(1);
out_char char(1);
dec_char number;
prev_space boolean := false;
begin
--dbms_output.put_line('In string: ' || in_string);
in_length := LENGTH(in_string);
while cnt < in_length
LOOP
cnt := cnt + 1;
in_char := substr(in_string, cnt, 1);
dec_char := ascii(in_char);
-- blank out non alphanumerics
IF (
(dec_char >= 48 AND dec_char <= 57) OR
(dec_char >= 65 AND dec_char <= 90) OR
(dec_char >= 97 AND dec_char <= 122)
) THEN
--keep it
out_char := in_char;
ELSE
out_char := ' ';
END IF;
IF (NOT(prev_space AND out_char = ' ')) THEN
out_string := out_string || out_char;
END IF;
<<endloop>>
IF (out_char = ' ') THEN
prev_space := true;
ELSE
prev_space := false;
END IF;
END LOOP;
return trim(upper(out_string));
end;
ALTER SESSION SET PLSQL_CODE_TYPE=NATIVE;
ALTER function clean_string COMPILE;
And to test, I pulled 5 million rows from a table and cleaned some strings:
set serveroutput on
declare
cursor sel_cur1 is
select name, clean_string(name) as cln_name,
address1, clean_string(address1) as cln_addr1,
address2, clean_string(address2) as cln_addr2,
city, clean_string(city) as cln_city,
state, clean_string(state) as cln_state,
postalcode, clean_string(postalcode) as cln_zip
from my_table
where rownum <= 5000000;
cursor sel_cur2 is
select name,
address1,
address2,
city,
state,
postalcode
from my_table
where rownum <= 5000000;
l_cnt integer := 0;
l_cln_name varchar2(100);
l_cln_addr1 varchar2(100);
l_cln_addr2 varchar2(100);
l_cln_city varchar2(100);
l_cln_state varchar2(100);
l_cln_zip varchar2(100);
l_interval interval day to second(4);
l_start timestamp;
l_end timestamp;
begin
l_start := systimestamp;
for rec in sel_cur2
loop
l_cnt := l_cnt + 1;
l_cln_name := clean_string(rec.name);
l_cln_addr1 := clean_string(rec.address1);
l_cln_addr2 := clean_string(rec.address2);
l_cln_city := clean_string(rec.city);
l_cln_state := clean_string(rec.state);
l_cln_zip := clean_string(rec.postalcode);
end loop;
l_end := systimestamp;
l_interval := l_end - l_start;
dbms_output.put_line('Procedural approach timing: ' || l_interval);
-------------------------------------------------
l_cnt := 0;
l_start := systimestamp;
for rec in sel_cur1
loop
-- cleaning already done in SQL
l_cnt := l_cnt + 1;
end loop;
l_end := systimestamp;
l_interval := l_end - l_start;
dbms_output.put_line('SQL approach timing: ' || l_interval);
-------------------------------------------------
l_cnt := 0;
l_start := systimestamp;
for rec in sel_cur2
loop
l_cnt := l_cnt + 1;
l_cln_name := UPPER(TRIM(REGEXP_REPLACE(REGEXP_REPLACE(rec.name, '[^0-9A-Za-z ]', ' '),'( )* ',' ')));
l_cln_addr1 := UPPER(TRIM(REGEXP_REPLACE(REGEXP_REPLACE(rec.address1, '[^0-9A-Za-z ]', ' '),'( )* ',' ')));
l_cln_addr2 := UPPER(TRIM(REGEXP_REPLACE(REGEXP_REPLACE(rec.address2, '[^0-9A-Za-z ]', ' '),'( )* ',' ')));
l_cln_city := UPPER(TRIM(REGEXP_REPLACE(REGEXP_REPLACE(rec.city, '[^0-9A-Za-z ]', ' '),'( )* ',' ')));
l_cln_state := UPPER(TRIM(REGEXP_REPLACE(REGEXP_REPLACE(rec.state, '[^0-9A-Za-z ]', ' '),'( )* ',' ')));
l_cln_zip := UPPER(TRIM(REGEXP_REPLACE(REGEXP_REPLACE(rec.postalcode, '[^0-9A-Za-z ]', ' '),'( )* ',' ')));
end loop;
l_end := systimestamp;
l_interval := l_end - l_start;
dbms_output.put_line('Existing approach timing: ' || l_interval);
end;
And the output was:
Procedural approach timing: +00 00:02:04.0320
SQL approach timing: +00 00:02:49.4326
Existing approach timing: +00 00:05:50.1607
Also, the native compilation seems to only help a procedural approach to the processing (rather than calling the function from a SQL query), but appears to be much faster than the regexp_replace solution. Hope that helps.
First, let me say that I am not really answering my own question, but I am accepting tbone's answer. The reason for providing this answer, is the comments don't let me post what I really want.
I created a function almost identical to tbone's with a couple of tweaks, got rid of the UPPER by changing how I handle the lower case range of characters, and changed numbers to binary_integers.
FUNCTION CLEAN_STRING(IN_STRING in VARCHAR2) RETURN VARCHAR2
AS
OUT_STRING VARCHAR2(32767) := '';
IN_LENGTH BINARY_INTEGER;
CNT BINARY_INTEGER := 0;
IN_CHAR CHAR(1);
OUT_CHAR CHAR(1);
DEC_CHAR BINARY_INTEGER;
PREV_SPACE BOOLEAN := FALSE;
BEGIN
IN_LENGTH := LENGTH(IN_STRING);
WHILE CNT < IN_LENGTH
LOOP
CNT := CNT + 1;
IN_CHAR := SUBSTR(IN_STRING, CNT, 1);
DEC_CHAR := ASCII(IN_CHAR);
-- blank out non alphanumerics
IF ((DEC_CHAR >= 48 AND DEC_CHAR <= 57) OR
(DEC_CHAR >= 65 AND DEC_CHAR <= 90))
THEN
--keep it
OUT_CHAR := IN_CHAR;
ELSE
IF (DEC_CHAR >= 97 AND DEC_CHAR <= 122)
THEN
OUT_CHAR := CHR(DEC_CHAR - 32);
ELSE
OUT_CHAR := ' ';
END IF;
END IF;
IF (NOT(PREV_SPACE AND OUT_CHAR = ' '))
THEN
OUT_STRING := OUT_STRING || OUT_CHAR;
END IF;
<<endloop>>
IF (OUT_CHAR = ' ') THEN
PREV_SPACE := TRUE;
ELSE
PREV_SPACE := FALSE;
END IF;
END LOOP;
RETURN TRIM(OUT_STRING);
END CLEAN_STRING;
I then created a simple test rig like tbone did, but I tested the three different routines against each other. First I verify that they all return the same results and then time each routine. Here is the test rig;
set serveroutput on
DECLARE
CURSOR PATHMAST_CURS
IS
SELECT PATHMAST_TEXT_DIAGNOSIS FROM PATHMAST WHERE ROWNUM < 100000;
DUMMY CLOB;
DUMMY_1 CLOB;
DUMMY_2 CLOB;
l_interval interval day to second(4);
l_start timestamp;
l_end timestamp;
diff_count_1 binary_integer := 0;
diff_count_2 binary_integer := 0;
BEGIN
FOR PATH_REC IN PATHMAST_CURS
LOOP
DUMMY := UPPER(TRIM(REGEXP_REPLACE(REGEXP_REPLACE(NVL(PATH_REC.PATHMAST_TEXT_DIAGNOSIS,' '), '[^0-9A-Za-z ]', ' '),'( )* ',' ')));
DUMMY_1 := pathmast_utility_3.CLEAN_STRING(NVL(PATH_REC.PATHMAST_TEXT_DIAGNOSIS,' '));
DUMMY_2 := regexp_replace(trim(translate(NVL(PATH_REC.PATHMAST_TEXT_DIAGNOSIS,' '),'abcdefghijklmnopqrstuvwxyz`~!##$%^&*()''_+-={[}]|/\":;,.<>?µ’±€'||chr(9),'ABCDEFGHIJKLMNOPQRSTUVWXYZ ')),'( )* ',' ');
IF DUMMY_1 != DUMMY
THEN
diff_count_1 := diff_count_1 + 1;
END IF;
IF DUMMY_2 != DUMMY
THEN
diff_count_2 := diff_count_2 + 1;
dbms_output.put_line('Regexp: ' || DUMMY);
dbms_output.put_line('Translate: ' || DUMMY_2);
END IF;
END LOOP;
dbms_output.put_line('CLEAN_STRING differences: ' || diff_count_1);
dbms_output.put_line('Translate differences: ' || diff_count_2);
l_start := systimestamp;
FOR PATH_REC IN PATHMAST_CURS
LOOP
DUMMY := UPPER(TRIM(REGEXP_REPLACE(REGEXP_REPLACE(PATH_REC.PATHMAST_TEXT_DIAGNOSIS, '[^0-9A-Za-z ]', ' '),'( )* ',' ')));
END LOOP;
l_end := systimestamp;
l_interval := l_end - l_start;
dbms_output.put_line('Regexp approach timing: ' || l_interval);
-------------------------------------------------
l_start := systimestamp;
FOR PATH_REC IN PATHMAST_CURS
LOOP
DUMMY := pathmast_utility_3.CLEAN_STRING(PATH_REC.PATHMAST_TEXT_DIAGNOSIS);
END LOOP;
l_end := systimestamp;
l_interval := l_end - l_start;
dbms_output.put_line('CLEAN_STRING approach timing: ' || l_interval);
-------------------------------------------------
l_start := systimestamp;
FOR PATH_REC IN PATHMAST_CURS
LOOP
DUMMY := regexp_replace(trim(translate(NVL(PATH_REC.PATHMAST_TEXT_DIAGNOSIS,' '),'abcdefghijklmnopqrstuvwxyz`~!##$%^&*()''_+-={[}]|/\":;,.<>?µ’±€'||chr(9),'ABCDEFGHIJKLMNOPQRSTUVWXYZ ')),'( )* ',' ');
END LOOP;
l_end := systimestamp;
l_interval := l_end - l_start;
dbms_output.put_line('TRANSLATE approach timing: ' || l_interval);
-------------------------------------------------
END;
And here are the results;
anonymous block completed
CLEAN_STRING differences: 0
Translate differences: 0
Regexp approach timing: +00 00:00:52.9160
CLEAN_STRING approach timing: +00 00:00:05.5220
TRANSLATE approach timing: +00 00:00:13.4320
This is all without compiling native. So tbone is the big winner. Thank you tbone.
If for whatever reason you want/need to use the translate version, you should build the translate string programmatically in order to get all of the special characters.
Perhaps, you can use TRANSLATE instead of regex to remove special characters and convert lower case to upper case.
regexp_replace(
trim(
translate(x,
'abcdefghijklmnopqrstuvwxyz`~!##$%^&*()_+-={[}]|/\"'':;,.<>?',
'ABCDEFGHIJKLMNOPQRSTUVWXYZ '
)
),
' {2,}',
' '
)
Tried it on a table with 1000 rows and column with random characters from anywhere between 1 to 4000.
Resulted in around 35% less time.(Did not try in PLSQL).
I have a String stored in a table in the following key-value format: "Key1☺Value1☺Key2☺Value2☺KeyN☺ValueN☺".
Given a Key how can I extract the Value? Is regex the easiest way to handle this? I am new to PL/SQL as well as Regex.
In this case, I would use just a regular split and iterate through the resulting array.
public string GetValue(string keyValuePairedInput, string key, char separator)
{
var split = keyValuePairedInput.Split(separator);
if(split.Lenght % 2 == 1)
throw new KeyWithoutValueException();
for(int i = 0; i < split.Lenght; i += 2)
{
if(split[i] == key)
return split[i + 1];
}
throw new KeyNotFoundException();
}
(this was not compiled and is not pl/sql anyway, treat it as pseudocode ☺)
OK I hear your comment...
Making use of pl/sql functions, you might be able to use something like this:
select 'key' as keyValue,
(instr(keyValueStringField, keyValue) + length(keyValue) + 1) as valueIndex,
substr(keyValueStringField, valueIndex, instr(keyValueStringField, '\1', valueIndex) - valueIndex) as value
from Table
For this kind of string slicing and dicing in PL/SQL you will probably have to use regular expressions. Oracle has a number of regular expression functions you can use. The most commonly used one is REGEXP_LIKE which is very similar to the LIKE operator but does RegEx matching.
However you probably need to use REGEXP_INSTR to find the positions where the separators are then use the SUBSTR function to slice up the string at the matched positions. You could also consider using REGEXP_SUBSTR which does the RegEx matching and slicing in one step.
As an alternative to regular expressions...
Assuming you have an input such as this:
Key1,Value1|Key2,Value2|Key3,Value3
You could use some PL/SQL as shown below:
FUNCTION get_value_by_key
(
p_str VARCHAR2
, p_key VARCHAR2
, p_kvp_separator VARCHAR2
, p_kv_separator VARCHAR2
) RETURN VARCHAR2
AS
v_key VARCHAR2(32767);
v_value VARCHAR2(32767);
v_which NUMBER;
v_cur VARCHAR(1);
BEGIN
v_which := 0;
FOR i IN 1..length(p_str)
LOOP
v_cur := substr(p_str,i,1);
IF v_cur = p_kvp_separator
THEN
IF v_key = p_key
THEN
EXIT;
END IF;
v_key := '';
v_value := '';
v_which := 0;
ELSIF v_cur = p_kv_separator
THEN
v_which := 1;
ELSE
IF v_which = 0
THEN
v_key := v_key || v_cur;
ELSE
v_value := v_value || v_cur;
END IF;
END IF;
END LOOP;
IF v_key = p_key
THEN
RETURN v_value;
END IF;
raise_application_error(-20001, 'key not found!');
END;
To get the value for 'Key2' you could do this (assuming your function was in a package called test_pkg):
SELECT test_pkg.get_value_by_key('Key1,Value1|Key2,Value2|Key3,Value3','Key2','|',',') FROM dual