How to Optimize PL/SQL code using Bulk collect/FORALL? - sql

pl/sql code taking too much time to remove characters in all tables
begin
for i in ( select TABLE_NAME,COLUMN_NAME from all_tab_columns
where owner='BILL' and data_length > 1 and table_name not like 'SYS_EXPORT_SCHEMA%' and table_name not like 'BIN%' and data_type ='VARCHAR2'
and column_name not like '%RR_NO%' and column_name not like '%RRNO%' order by 5 desc )
loop
execute immediate 'UPDATE '|| i.TABLE_NAME || ' SET ' ||i.COLUMN_NAME || '= REPLACE (' ||i.COLUMN_NAME ||',CHR(10),'||chr(39)||chr(39)|| ') WHERE INSTR('||i.COLUMN_NAME ||',CHR(10))>0';
execute immediate 'UPDATE '|| i.TABLE_NAME || ' SET ' ||i.COLUMN_NAME || '= REPLACE (' ||i.COLUMN_NAME ||',CHR(13),'||chr(39)||chr(39)|| ') WHERE INSTR('||i.COLUMN_NAME ||',CHR(13))>0';
dbms_output.put_line(i.TABLE_NAME||' - '||i.COLUMN_NAME||'- '||sql%rowcount);
end loop;
commit;
end;
pls help me by writing using Bulk collect/FORALL
Right now i am doing Manually using
select ' UPDATE '|| TABLE_NAME || ' SET ' ||COLUMN_NAME || '= REPLACE (' ||COLUMN_NAME ||',CHR(10),'||chr(39)||chr(39)|| ') WHERE INSTR('||COLUMN_NAME ||',CHR(10))>0;'
from all_tab_columns
where owner='BILL' and data_length > 1 and table_name not like 'SYS_EXPORT_SCHEMA%' and table_name not like 'BIN%'
and data_type ='VARCHAR2' and column_name not like '%RR_NO%' and column_name not like '%RRNO%';
select ' UPDATE '|| TABLE_NAME || ' SET ' ||COLUMN_NAME || '= REPLACE (' ||COLUMN_NAME ||',CHR(13),'||chr(39)||chr(39)|| ') WHERE INSTR('||COLUMN_NAME ||',CHR(13))>0;'
from all_tab_columns
where owner='BILL' and data_length > 1 and table_name not like 'SYS_EXPORT_SCHEMA%'
and table_name not like 'BIN%' and data_type ='VARCHAR2' and column_name not like '%RR_NO%' and column_name not like '%RRNO%';
copying this SQL results and executing manually.
it was taking more than 1 hour to run scripts.
DECLARE
CURSOR c1 IS SELECT TABLE_NAME,COLUMN_NAME FROM ALL_TAB_COLUMNS
WHERE OWNER='BILL' AND DATA_LENGTH > 1 AND TABLE_NAME NOT LIKE 'SYS_EXPORT_SCHEMA%' AND TABLE_NAME NOT LIKE 'BIN%' AND DATA_TYPE ='VARCHAR2'
AND COLUMN_NAME NOT LIKE '%RR_NO%' AND COLUMN_NAME NOT LIKE '%RRNO%';
TYPE RecList IS TABLE OF c1%ROWTYPE;
recs RecList;
BEGIN
BEGIN
OPEN c1;
LOOP
FETCH c1 BULK COLLECT INTO recs LIMIT 500;
EXIT WHEN c1%NOTFOUND;
FOR i IN recs.FIRST .. recs.LAST
LOOP
EXECUTE IMMEDIATE 'UPDATE '|| recs(i).TABLE_NAME || ' SET ' ||recs(i).COLUMN_NAME || '= REPLACE (' ||recs(i).COLUMN_NAME ||',CHR(10),'||CHR(39)||CHR(39)|| ') WHERE INSTR('||recs(i).COLUMN_NAME ||',CHR(10))>0';
dbms_output.put_line(recs(i).TABLE_NAME||' - '||recs(i).COLUMN_NAME||' - '||sql%rowcount);
EXECUTE IMMEDIATE 'UPDATE '|| recs(i).TABLE_NAME || ' SET ' ||recs(i).COLUMN_NAME || '= REPLACE (' ||recs(i).COLUMN_NAME ||',CHR(13),'||CHR(39)||CHR(39)|| ') WHERE INSTR('||recs(i).COLUMN_NAME ||',CHR(13))>0';
dbms_output.put_line(recs(i).TABLE_NAME||' - '||recs(i).COLUMN_NAME||' - '||sql%rowcount);
END LOOP;
END LOOP;
exception when others then
dbms_output.put_line(sqlcode||sqlerrm);
CLOSE C1;
END;
commit;
END;
/
i written one query Is's working,Is there any tips to optimize this query further.

The below is not tested but it just to give you an idea, try to prepare the values first send add them to the update. then make sure you have an index on the table covering the column. when you use functions it will make harder for the DML to read indexes. also in such way you are using bind variable method (soft parsing) which it will enhance the performance much better.
select REPLACE (' ||i.COLUMN_NAME ||',CHR(10),'||chr(39)||chr(39)|| ') into R_COL from dual;
select INSTR('||i.COLUMN_NAME ||',CHR(10)) into I_COL from dual;
UPDATE '|| i.TABLE_NAME || ' SET ' ||i.COLUMN_NAME || ' = R_COL WHERE I_COL >0;

Related

oracle: display results of dynamic sql based on antoher sql

I would like to display results of dynamic sql based on antoher sql, but get error message. My code:
DECLARE
sql_qry VARCHAR2(1000) := NULL;
TYPE results IS
TABLE OF all_tab_columns%rowtype;
results_tbl results;
BEGIN
FOR i IN (
SELECT
*
FROM
all_tab_columns
WHERE
owner = 'OWNER_XYZ'
AND upper(column_name) LIKE '%COLUMN_XYZ%'
ORDER BY
table_name,
column_name
) LOOP
sql_qry := ' SELECT DISTINCT '
|| i.column_name
|| ' as column_name '
|| ' FROM '
|| i.owner
|| '.'
|| i.table_name
|| ' WHERE SUBSTR('
|| i.column_name
|| ',1,1) = ''Y''';
EXECUTE IMMEDIATE sql_qry BULK COLLECT
INTO results_tbl;
dbms_output.put_line(results_tbl);
END LOOP;
END;
I get the error message:
PLS-00306: wrong number or types of arguments in call to 'PUT_LINE'
In fact I need the results of all queries with an union between them like that
[1] [1]: https://i.stack.imgur.com/llxzr.png
Your dynamic query is selecting a single column, but you are bulk collecting into results_tbl, which is of type results, based on all_tab_columns%rowtype - which has lots of columns.
If you define your collection type as a single column of the data type you need, i.e. some length of string:
DECLARE
sql_qry VARCHAR2(1000) := NULL;
TYPE results IS
TABLE OF varchar2(4000);
results_tbl results;
...
You will then bulk collect a single column into that single-column collection. To display the results you need to loop over the collection:
FOR j IN 1..results_tbl.COUNT loop
dbms_output.put_line(results_tbl(j));
END LOOP;
so the whole block becomes:
DECLARE
sql_qry VARCHAR2(1000) := NULL;
TYPE results IS
TABLE OF varchar2(4000);
results_tbl results;
BEGIN
FOR i IN (
SELECT
*
FROM
all_tab_columns
WHERE
owner = 'OWNER_XYZ'
AND upper(column_name) LIKE '%COLUMN_XYZ%'
ORDER BY
table_name,
column_name
) LOOP
sql_qry := ' SELECT DISTINCT '
|| i.column_name
|| ' as column_name '
|| ' FROM '
|| i.owner
|| '.'
|| i.table_name
|| ' WHERE SUBSTR('
|| i.column_name
|| ',1,1) = ''Y''';
EXECUTE IMMEDIATE sql_qry BULK COLLECT
INTO results_tbl;
FOR j IN 1..results_tbl.COUNT loop
dbms_output.put_line(results_tbl(j));
END LOOP;
END LOOP;
END;
/
However, you can also do this without PL/SQL, using a variation on an XML trick. You can get the results of the dynamic query as an XML document using something like:
select dbms_xmlgen.getxmltype(
'select distinct "' || column_name || '" as value'
|| ' from "' || owner || '"."' || table_name || '"'
|| ' where substr("' || column_name || '", 1, 1) = ''Y'''
)
from all_tab_columns
where owner = 'OWNER_XYZ'
and upper(column_name) like '%COLUMN_XYZ%';
and then extract the value you want from that:
with cte (xml) as (
select dbms_xmlgen.getxmltype(
'select distinct "' || column_name || '" as value'
|| ' from "' || owner || '"."' || table_name || '"'
|| ' where substr("' || column_name || '", 1, 1) = ''Y'''
)
from all_tab_columns
where owner = 'OWNER_XYZ'
and upper(column_name) like '%COLUMN_XYZ%'
)
select x.value
from cte
cross apply xmltable(
'/ROWSET/ROW'
passing cte.xml
columns value varchar2(4000) path 'VALUE'
) x;
You can also easily include the table each value came from if you want that information (and the owner, and actual column name, etc.).
db<>fiddle showing both approaches.

How to declare a number variable where I can save th count of table in my loop

I work wirh oracle Database. I have a plsql code where i run a query in a loop for multiple tables. so, table name is a variable in my code. I would like to have another variable (a single number) that I can call inside the loop and every time it counts the total rows of each table for me
declare
Cursor C_TABLE is
select trim(table_name) as table_name
from all_tables
where table_name in ('T1', 'T2', 'T3');
V_ROWNUM number;
begin
for m in C_TABLE
loop
for i in ( select column_name
from (
select c.column_name
from all_tab_columns c
where c.table_name = m.table_name
and c.owner = 'owner1'
)
)
loop
--I have this:
execute immediate ' insert into MY-table value (select ' || i.column_name || ' from ' || m.table_name || ')';
--I want this but it does not work of course:
V_ROWNUM := execute immediate 'select count(*) from ' || m.table_name;
execute immediate ' insert into MY-table value (select ' || i.column_name || ', ' || V_ROWNUM || ' from ' || m.table_name || ')';
end loop;
end loop;
end;
/
I count not use the "insert into" because I am not selecting from 1 table but the table I want to select from changes every round.
There are three things wrong with your dynamic SQL.
EXECUTE IMMEDIATE is not a function: the proper syntax is execute immediate '<<query>>' into <<variable>>.
An INSERT statement takes a VALUES clause or a SELECT but not both. SELECT would be very wrong in this case. Also note that it's VALUES not VALUE.
COLUMN_NAME is a string literal in the dynamic SQL so it needs to be in quotes. But because the SQL statement is itself a string, quotes in dynamic strings need to be escaped so it should be `'''||column_name||'''.
So the corrected version will look something like this
declare
Cursor C_TABLE is
select trim(table_name) as table_name
from all_tables
where table_name in ('T1', 'T2', 'T3');
V_ROWNUM number;
begin
for m in C_TABLE
loop
for i in ( select column_name
from (
select c.column_name
from all_tab_columns c
where c.table_name = m.table_name
and c.owner = 'owner1'
)
)
loop
execute immediate 'select count(*) from ' || m.table_name into V_ROWNUM;
execute immediate 'insert into MY_table values ( ''' || i.column_name || ''', ' || V_ROWNUM || ')';
end loop;
end loop;
end;
/
Dynamic SQL is hard because it turns compilation errors into runtime errors. It is good practice to write the statements first as static SQL. Once you have got the basic syntax right you can convert it into dynamic SQL.
you can't assign the result of execute immediate to a variable. it is not a function.
but you can do it by using the into_clause e.g.
execute immediate 'select count(*) from ' || m.table_name into V_ROWNUM ;

plsql List all table.column containing null values

I'd like to find all column of a set of table with null values in them.
I can find the table and column names
SELECT TABLE_NAME, COLUMN_NAME
FROM user_tab_cols
where nullable='Y'
and table_name in ('myTalbe', 'myTable2');
And also check if the are nulls
select count(*) from myTable where myColumn is null;
but how can I put this toghether to have as result
table_name column_name
myTable myColumn
myTable myCol2
myTable2 col4
An approach could be with some dynamic SQL, but this would require some PL/SQL code; the following only uses SQL to get the result you need:
select *
from (
select table_name,
column_name,
to_number(extractvalue(xmltype(dbms_xmlgen.getxml('select count(*) c from '||table_name || ' where ' || column_name || ' is null')),'/ROWSET/ROW/C')) as rowcount
from user_tab_columns
where nullable='Y'
and table_name in ('myTalbe', 'myTable2')
)
where rowcount > 0
This could be an approach with dynamic SQL:
declare
type tableOfNumber is table of number;
type tableOfChar is table of varchar2(30);
--
vSQl varchar2(4000);
vListNumbers tableOfNumber;
vListTables tableOfChar;
vListColumns tableOfChar;
begin
select listagg( 'select ''' ||
table_name || ''' as table_name, ''' ||
column_name || ''' as column_name, count(*) as rowCount from ' ||
table_name ||
' where ' ||
column_name ||
' is null having count(*) > 0' ,
' UNION ALL '
) within group ( order by table_name, column_name)
into vSQL
from user_tab_columns
where nullable='Y'
and table_name in ('myTalbe', 'myTable2');
--
dbms_output.put_line(vSQL);
/* whatever you may want to do with the query */
/* for example, fetch into some variables and print the result */
execute immediate vSQL
bulk collect into vListTables, vListColumns, vListNumbers;
--
if vListTables.count() > 0 then
for i in vListTables.first .. vListTables.last loop
dbms_output.put_line('Table ' || vListTables(i) ||
', column ' || vListColumns(i) ||
', number of nulls: ' || vListNumbers(i)
);
end loop;
end if;
end;
Here's a routine I wrote a while back to do exactly that. It will output the required DDL to make those columns that are nullable (but do not contain any nulls) not nullable.
https://connormcdonald.wordpress.com/2016/03/11/tightening-up-your-data-model/
It can do the task for a schema or a single table.

search entire oracle database for part of string

I'm trying to find a specific string in an entire Oracle database.
I've followed the example in another topic on here (Search All Fields In All Tables For A Specific Value (Oracle)), and it's working when the string is the whole value in a column. But I need to search for the string as part of the column.
For example, if i search for 'Alert' it should return all columns with 'Alert' in and all columns with 'Alert_QB'
This is the query at the moment:
DECLARE
match_count INTEGER;
BEGIN
FOR t IN (SELECT owner, table_name, column_name
FROM all_tab_columns
WHERE data_type LIKE '%CHAR%') LOOP
EXECUTE IMMEDIATE
'SELECT COUNT(*) FROM ' || t.owner || '.' || t.table_name ||
' WHERE '||t.column_name||' = :1'
INTO match_count
USING 'ALERT';
EXCEPTION when others then
null;
end;
IF match_count > 0 THEN
dbms_output.put_line( t.table_name ||' '||t.column_name||' '||match_count );
END IF;
END LOOP;
END;
/
I think it's near the "USING 'ALERT';" line that I need to add something but I don't know what.
Thanks
Change it to
EXECUTE IMMEDIATE
'SELECT COUNT(*) FROM ' || t.owner || '.' || t.table_name ||
' WHERE '||t.column_name||' like :1'
INTO match_count
USING '%ALERT%';
You can concatenate the bind variable with the wildcard % characters:
EXECUTE IMMEDIATE
'SELECT COUNT(*) FROM ' || t.owner || '.' || t.table_name ||
' WHERE '||t.column_name||' LIKE ''%'' || :1 || ''%'''
INTO match_count
USING 'ALERT';
Note that the single quotes have to be escaped by doubling them up.

Oracle: how to run this query (generated column names)

I need to run a query on generated generated column names.
Here's the query:
select 'col_'||4 from MY_TABLE
Note:
"4" is a variable that is passed to this query from within the Java code
MY_TABLE is a table that contain columns with names (col_4, col_5, etc..)
Inside Oracle you need use dynamic SQL. (YourVariable value is 4 for your example)
EXECUTE IMMEDIATE ' select col_' || YourVariable || ' from MY_TABLE ';
From Java you can build any SQL and execute them
To run a dynamic SELECT statement, you have two choices:
For single row selects, you use EXECUTE IMMEDIATE ... INTO:
EXECUTE IMMEDIATE 'select col_' || l_num || ' from MY_TABLE WHERE id = 37' INTO l_result;
For selecting multiple rows, you can use a dynamic cursor:
DECLARE
TYPE MyCurType IS REF CURSOR;
my_cv MyCurType;
BEGIN
OPEN emp_cv FOR 'select col_' || l_num || ' from MY_TABLE';
...
END;
This code generates a SELECT that returns the tables with their column name:
SELECT
'SELECT ' ||(
SELECT
LISTAGG(
c.TABLE_NAME || '.' || c.COLUMN_NAME || ' AS "' || c.TABLE_NAME || '.' || c.COLUMN_NAME || '"',
', '
) WITHIN GROUP(
ORDER BY
c.TABLE_NAME
) "TABLE_NAMES"
FROM
USER_TAB_COLS c
WHERE
TABLE_NAME IN(
'PESSOA',
'PESSOA_FISICA',
'PESSOA_JURIDICA'
)
)|| 'FROM PERSON;'
FROM
DUAL;