How to View Schema in Oracle

Galaxy Glossary

How do I view tables and columns in an Oracle schema?

Displays the tables, columns, indexes, and other objects that belong to a specific Oracle schema.

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Description

What is the fastest way to list all tables in a schema?

Query the ALL_TABLES or USER_TABLES data dictionary views. ALL_TABLES shows objects you have privileges on, while USER_TABLES shows objects you own.

SELECT table_name FROM all_tables WHERE owner = 'ECOMMERCE';

How do I see all columns for a single table?

Use ALL_TAB_COLUMNS or DESC. For more details including data types and nullable flags, prefer the view.

SELECT column_name, data_type, nullable FROM all_tab_columns WHERE owner = 'ECOMMERCE' AND table_name = 'PRODUCTS';

Can I get indexes, constraints, and foreign keys in one place?

Yes. Combine ALL_INDEXES, ALL_CONSTRAINTS, and ALL_CONS_COLUMNS to assemble full structural metadata.

SELECT i.index_name, c.constraint_type, col.column_name FROM all_indexes i JOIN all_constraints c ON i.owner = c.owner AND i.index_name = c.index_name JOIN all_cons_columns col ON c.owner = col.owner AND c.constraint_name = col.constraint_name WHERE i.table_owner = 'ECOMMERCE' AND i.table_name = 'ORDERS';

How do I see dependencies between objects?

Use ALL_DEPENDENCIES to trace which PL/SQL packages, views, or triggers rely on specific tables.

Is there a single query that outputs a full schema snapshot?

Create a script that unions multiple dictionary views, or leverage Oracle’s DBMS_METADATA.GET_DDL to extract the DDL for each object.

SELECT DBMS_METADATA.GET_DDL('TABLE', table_name, owner) AS ddl FROM all_tables WHERE owner = 'ECOMMERCE';

Best practices

Filter by OWNER to avoid cross-schema noise.
Grant SELECT_CATALOG_ROLE to read system views safely.
Store schema scripts in version control for reproducibility.

Why How to View Schema in Oracle is important

How to View Schema in Oracle Example Usage


-- Get column metadata for OrderItems table
SELECT column_name,
       data_type,
       data_length,
       nullable
FROM   all_tab_columns
WHERE  owner      = 'ECOMMERCE'
  AND  table_name = 'ORDERITEMS'
ORDER  BY column_id;

How to View Schema in Oracle Syntax


-- List tables
SELECT table_name
FROM   all_tables
WHERE  owner = 'ECOMMERCE';

-- List columns for a specific table
SELECT column_name, data_type, nullable
FROM   all_tab_columns
WHERE  owner      = 'ECOMMERCE'
  AND  table_name = 'PRODUCTS';

-- Show indexes on Orders table
SELECT index_name, uniqueness
FROM   all_indexes
WHERE  table_owner = 'ECOMMERCE'
  AND  table_name  = 'ORDERS';

-- Pull full DDL for each table
SELECT DBMS_METADATA.GET_DDL('TABLE', table_name, owner)
FROM   all_tables
WHERE  owner = 'ECOMMERCE';

Common Mistakes

Using USER_ views when connected as a low-privilege user. USER_ views only show objects you own, so critical tables may be invisible. Fix by querying ALL_ views or asking for SELECT_CATALOG_ROLE.
Forgetting to quote mixed-case object names. Oracle stores unquoted identifiers in uppercase. Always use uppercase or double-quote exact case when filtering by OWNER or TABLE_NAME.

Frequently Asked Questions (FAQs)

Does `SELECT * FROM dba_tables` require special rights?

Yes. You need the DBA role or explicit SELECT on those DBA_ views.

What’s the difference between ALL_ and DBA_ views?

ALL_ views show objects you can access while DBA_ views show everything in the database. Use DBA_ only if you are a DBA.

Can I export a schema’s DDL?

Yes. Use DBMS_METADATA.GET_DDL or the expdp utility with the SCHEMAS parameter.

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