Searching all fields in an Oracle database.
I am working with a rather large Oracle database with thousands of tables. This is used for a Windows based application. Unfortunately the original developer is gone and my client ask for me to pull data out of the database.
As of now, I am trying to find the tables that contain specific pieces of data. I am attempting to do this based on values that I know exist in the database. I know these values are not generated by some type of formula or in a blob field. I am using
Oracle SQL Developer for this.
I have an extensive background in SQL, but not Oracle. Any suggestions regarding running a query to look for a column with one of the known values would be greatly appreciated.
As of now, I am trying to find the tables that contain specific pieces of data. I am attempting to do this based on values that I know exist in the database. I know these values are not generated by some type of formula or in a blob field. I am using
Oracle SQL Developer for this.
I have an extensive background in SQL, but not Oracle. Any suggestions regarding running a query to look for a column with one of the known values would be greatly appreciated.
ASKER CERTIFIED SOLUTION
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To do exactly what you asked for in Oracle (search all tables for a particular value in a column) is certainly not easy. And, depending on the size of your database and on the size and speed of your server and storage system, running a query like this may take some minutes, hours, days or weeks.
As a couple examples from others demonstrate, yes, it is possible in Oracle to use "dynamic SQL" in Oracle stored procedures. (That is: use a query to construct a list of table and column names, then construct and process a query for each table and column combination.) But, Oracle stored procedures are *NOT* optimized for processing "dynamic SQL" like this in stored procedures. This is one of the significant differences between SQL Server and Oracle: Oracle stored procedures *ARE* optimized for static SQL statements, that is: SQL statements where the table and column names are known at compile time, and only the bind values (in "where" clauses or "insert ... values (...)" statements) are changed each time.
Also, this PL\SQL command in Oracle: "dbms_output.put_line..." is legal, but you usually have to explicitly execute a command like one of these first in order to see that output:
set serveroutput on;
exec dbms_output.enable(1000000
It may be faster to use Oracle's export (or DataPump export) utility to extract the contents of some of the tables to (mostly) text files, then use an O/S search utility to check for the character string(s) you are interested in. That may help you identify the table name(s), but that won't help you yet to identify the column(s). You may then need to use a "dynamic SQL" technique to search the columns, but if you at least have the table (or afew tables) identified, that should dramatically reduce the amount of time required.
As a couple examples from others demonstrate, yes, it is possible in Oracle to use "dynamic SQL" in Oracle stored procedures. (That is: use a query to construct a list of table and column names, then construct and process a query for each table and column combination.) But, Oracle stored procedures are *NOT* optimized for processing "dynamic SQL" like this in stored procedures. This is one of the significant differences between SQL Server and Oracle: Oracle stored procedures *ARE* optimized for static SQL statements, that is: SQL statements where the table and column names are known at compile time, and only the bind values (in "where" clauses or "insert ... values (...)" statements) are changed each time.
Also, this PL\SQL command in Oracle: "dbms_output.put_line..." is legal, but you usually have to explicitly execute a command like one of these first in order to see that output:
set serveroutput on;
exec dbms_output.enable(1000000
It may be faster to use Oracle's export (or DataPump export) utility to extract the contents of some of the tables to (mostly) text files, then use an O/S search utility to check for the character string(s) you are interested in. That may help you identify the table name(s), but that won't help you yet to identify the column(s). You may then need to use a "dynamic SQL" technique to search the columns, but if you at least have the table (or afew tables) identified, that should dramatically reduce the amount of time required.
ASKER
Thank you everyone for your input. I am reviewing your suggestions now.
Markgeer, Oracle SQL Developer has a “Database Export” feature which I am trying now.
Markgeer, Oracle SQL Developer has a “Database Export” feature which I am trying now.
I've requested that this question be deleted for the following reason:
Author has found a workaround (https://www.experts-exchange.com/R_42492.html)
Author has found a workaround (https://www.experts-exchange.com/R_42492.html)
TO_NUMBER(
EXTRACTVALUE(
xmltype(
DBMS_XMLGEN.
getxml(
'select count(*) X from '
|| table_name
|| ' where '
|| column_name
|| ' = ''your known value'''
)
),
'/ROWSET/ROW/X'
)
)
COUNT
FROM all_tab_cols
WHERE data_type = 'VARCHAR2' -- change this to whatever is appropriate