Identifying Sybase tables, fields, keys, constrain

问题:

I'm trying to set up a Sybase query that will give me the following output:

Table     KeyType      KeyNumber      Column
table1    PK           1              table1_id
table1    FK           2              table2_id    
table1    FK           3              table3_id
table1    FK           4              table4_id
table1    Unique       5              table1_abc
table1    Unique       5              table1_def

In other words, I need the PK for each table, and every foreign key it has, as well as every unique key (not where a key has more than one element, such as the unique key above, this is identified by having the same KeyNumber).

I'm guessing I need to use sysobject, syscolumns, syskeys and sysconstraints but I can't seem to figure out how they interlink.

Thanks
Karl

回答1:

This is a start:

SELECT 
    t.name, 
    CASE k.type 
        WHEN 1 THEN 'PK' 
        WHEN 2 THEN 'FK'
        WHEN 3 THEN 'Common'
    END,
    c.name
FROM 
    sysobjects t INNER JOIN 
    syscolumns c ON c.id = t.id INNER JOIN
    syskeys k ON k.id = t.id AND c.colid IN (k.key1, k.key2, k.key3, k.key4, k.key5, k.key6, k.key7, k.key8)
WHERE 
    t.type = 'U' AND k.type in (1,2)

It does not include the key ID, for that I guess you could somehow hash the non-null table ID and keyN columns to produce a unique ID for the key.

It also does not include unique indexes. For that you would want to UNION with something along the lines of:

SELECT 
    t.name, 
    'Unique',
    c.name
FROM 
    sysobjects t INNER JOIN 
    syscolumns c ON c.id = t.id INNER JOIN
    sysindexes i ON i.id = t.id
WHERE t.type = 'U'

Check out the Sybase manual page for sysindexes on how to filter it.