How to get db Schema & Constraints?

To get Schema depending on your db type you should run a query in your SQL client and then export the results in CSV.

Keep in mind that this will only return the information about your tables structure and will NOT include any actual data from these tables.

Postgres Query

Schema

Select table_name, column_name, data_type from information_schema.columns where table_schema not in ('information_schema', 'pg_catalog', 'mysql', 'performance_schema', 'sys');

Constraints

SELECT tc.constraint_name, tc.table_name, kcu.column_name, ccu.table_name AS foreign_table_name, ccu.column_name AS foreign_column_name FROM information_schema.table_constraints AS tc JOIN information_schema.key_column_usage AS kcu ON tc.constraint_name = kcu.constraint_name AND tc.table_schema = kcu.table_schema JOIN information_schema.constraint_column_usage AS ccu ON ccu.constraint_name = tc.constraint_name WHERE tc.constraint_type != 'CHECK';

If this constraints query above returned nothing, you can try the following one:

SELECT
    con.conname AS constraint_name,
    tbl.relname AS table_name,
    a.attname AS column_name,
    CASE 
        WHEN con.contype = 'p' THEN 'PRIMARY KEY'
        WHEN con.contype = 'u' THEN 'UNIQUE'
        WHEN con.contype = 'f' THEN 'FOREIGN KEY'
        WHEN con.contype = 'c' THEN 'CHECK'
    END AS constraint_type,
    CASE 
        WHEN con.confupdtype = 'a' THEN 'NO ACTION'
        WHEN con.confupdtype = 'r' THEN 'RESTRICT'
        WHEN con.confupdtype = 'c' THEN 'CASCADE'
        WHEN con.confupdtype = 'n' THEN 'SET NULL'
        WHEN con.confupdtype = 'd' THEN 'SET DEFAULT'
    END AS on_update,
    CASE 
        WHEN con.confdeltype = 'a' THEN 'NO ACTION'
        WHEN con.confdeltype = 'r' THEN 'RESTRICT'
        WHEN con.confdeltype = 'c' THEN 'CASCADE'
        WHEN con.confdeltype = 'n' THEN 'SET NULL'
        WHEN con.confdeltype = 'd' THEN 'SET DEFAULT'
    END AS on_delete
FROM
    pg_constraint con
    INNER JOIN pg_class tbl ON con.conrelid = tbl.oid
    INNER JOIN pg_attribute a ON a.attrelid = tbl.oid AND a.attnum = ANY(con.conkey)
WHERE
    tbl.relkind = 'r'
    AND tbl.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname = 'YOUR-SCHEMA-NAME')
ORDER BY
    table_name;

Make sure to replace the YOUR-SCHEMA-NAME part in the end with your actual schema name.

MySQL Query

Schema

select
    table_name,
    column_name,
    data_type
from
    information_schema.columns
where
    table_schema not in ('information_schema', 'pg_catalog', 'mysql', 'performance_schema', 'sys');

Constraints

select
    CONSTRAINT_NAME,
    TABLE_NAME,
    COLUMN_NAME,
    REFERENCED_TABLE_NAME,
    REFERENCED_COLUMN_NAME 
from
    information_schema.key_column_usage
where
    table_schema not in ('information_schema', 'pg_catalog', 'mysql', 'performance_schema', 'sys');

Oracle Query

Schema

SELECT 
    table_name,
    column_name,
    data_type
FROM 
    all_tab_columns
WHERE 
    owner NOT IN ('SYS', 'SYSTEM');

Constraints

SELECT 
    a.constraint_name, 
    a.table_name, 
    a.column_name, 
    c_pk.table_name AS referenced_table_name,
    b.column_name AS referenced_column_name
FROM 
    all_cons_columns a
JOIN 
    all_constraints c ON a.owner = c.owner
    AND a.constraint_name = c.constraint_name
JOIN 
    all_constraints c_pk ON c.r_owner = c_pk.owner
    AND c.r_constraint_name = c_pk.constraint_name
JOIN 
    all_cons_columns b ON c_pk.owner = b.owner
    AND c_pk.constraint_name = b.constraint_name
WHERE 
    c.constraint_type = 'R'
AND 
    a.owner NOT IN ('SYS', 'SYSTEM');