How to Efficiently Search Across All Tables in Oracle for a Specific Value?

Search for a specific value in all tables in Oracle database

Question:

In Oracle databases, especially when dealing with large databases, users may need to search for specific values ​​for each field in each table. This task can be challenging due to the potential length and complexity of such queries.

Solution:

One way to solve this problem is to utilize cursor-based technology to dynamically generate SQL queries. Here's a simplified example:

DECLARE
  CURSOR c_tab IS
    SELECT table_name, column_name
    FROM all_tab_columns
    WHERE owner = 'USER_NAME';
BEGIN
  FOR t IN c_tab LOOP
    EXECUTE IMMEDIATE
      'SELECT COUNT(*) FROM ' || t.table_name ||
      ' WHERE ' || t.column_name || ' = :1'
      INTO match_count
      USING '1/22/2008P09RR8';

    IF match_count > 0 THEN
      dbms_output.put_line( t.table_name || ' ' || t.column_name || ' ' || match_count );
    END IF;
  END LOOP;
END;
/

This query iterates through all tables and columns owned by a specific user, checking if each value matches the provided value. The results are displayed as table names, column names, and counts of matching rows.

Improve efficiency:

To optimize performance, further filters can be applied based on data type. For example, you can modify the query to focus only on columns of type '%CHAR%' because the specified value appears to be a character string.

Alternative:

As an alternative, PL/SQL can be used to embed dynamic SQL queries within a session, which may result in faster execution. Here is a sample code:

SET SERVEROUTPUT ON SIZE 100000

DECLARE
  match_count INTEGER;
BEGIN
  FOR t IN (SELECT owner, table_name, column_name
              FROM all_tab_columns
              WHERE owner <> 'SYS' AND data_type LIKE '%CHAR%') LOOP

    EXECUTE IMMEDIATE
      'SELECT COUNT(*) FROM ' || t.owner || '.' || t.table_name ||
      ' WHERE ' || t.column_name || ' = :1'
      INTO match_count
      USING '1/22/2008P09RR8';

    IF match_count > 0 THEN
      dbms_output.put_line( t.table_name || ' ' || t.column_name || ' ' || match_count );
    END IF;
  END LOOP;

END;
/

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