Select datatype of the field in postgres

Question

How do I get datatype of specific field from table in postgres ? For example I have the following table, student_details ( stu_id integer, stu_name varchar(30 ), joined_date timestamp );

In this using the field name / or any other way, I need to get the datatype of the specific field. Is there any possibility ?

Answer 1

You can get data types from the information_schema (8.4 docs referenced here, but this is not a new feature):

=# select column_name, data_type from information_schema.columns
-# where table_name = 'config';
    column_name     | data_type 
--------------------+-----------
 id                 | integer
 default_printer_id | integer
 master_host_enable | boolean
(3 rows)

Answer 2

You can use the pg_typeof() function, which also works well for arbitrary values.

SELECT pg_typeof("stu_id"), pg_typeof(100) from student_details limit 1;

Answer 3

run psql -E and then \d student_details

Answer 4

// READ opperation
// listName: The name of the list you want to get items from
// siteurl: The url of the site that the list is in.
// success: The function to execute if the call is sucesfull
// failure: The function to execute if the call fails
function getListItems(listName, siteurl, success, failure) {
    $.ajax({
        url: siteurl + "/_api/web/lists/getbytitle('" + listName + "')/items",
        method: "GET",
        headers: { "Accept": "application/json; odata=verbose" },
        success: function (data) {
            success(data);
        },
        error: function (data) {
            failure(data);
        }
    });
}

// CREATE Operation
// listName: The name of the list you want to get items from
// siteurl: The url of the site that the list is in. // title: The value of the title field for the new item
// success: The function to execute if the call is sucesfull
// failure: The function to execute if the call fails
function createListItemWithDetails(listName, siteUrl, title, success, failure) {

    var itemType = GetItemTypeForListName(listName);
    var item = {
        "__metadata": { "type": itemType },
        "Title": title
    };

    $.ajax({
        url: siteUrl + "/_api/web/lists/getbytitle('" + listName + "')/items",
        type: "POST",
        contentType: "application/json;odata=verbose",
        data: JSON.stringify(item),
        headers: {
            "Accept": "application/json;odata=verbose",
            "X-RequestDigest": $("#__REQUESTDIGEST").val()
        },
        success: function (data) {
            success(data);
        },
        error: function (data) {
            failure(data);
        }
    });
}

. http://blogs.msdn.com/b/uksharepoint/archive/2013/02/22/Manipulation-List-Items-In-SharePoint-Hosted-Apps-using-the-rest-api.aspx

다음 포스트는 NAPA 및 Client 객체 모델을 사용하여 앱을 만드는 방법을 보여줍니다.클라이언트 오브젝트 코드를 바꿀 수 있고 휴식을 사용할 수 있습니다. http://sharepointnadeem.blogspot.com/2013/12./sharepoint-2013-develop-sharepoint-2013.html

Answer 5

If you like 'Mike Sherrill' solution but don't want to use psql, I used this query to get the missing information:

select column_name,
case 
    when domain_name is not null then domain_name
    when data_type='character varying' THEN 'varchar('||character_maximum_length||')'
    when data_type='numeric' THEN 'numeric('||numeric_precision||','||numeric_scale||')'
    else data_type
end as myType
from information_schema.columns
where table_name='test'

with result:

column_name |     myType
-------------+-------------------
 test_id     | test_domain
 test_vc     | varchar(15)
 test_n      | numeric(15,3)
 big_n       | bigint
 ip_addr     | inet

Answer 6

현재 SP 컨텍스트가 앱 웹에 있기 때문에이 오류가 발생했습니다.따라서 HostWebURL을 사용하여 새 컨텍스트를 만들면 오류가 발생합니다.이를 사용해야합니다.

교체 :

context = new SP.ClientContext(hostweburl);

.

작성자 :

context = new SP.ClientContext();

.

Answer 7

Pulling data type from information_schema is possible, but not convenient (requires joining several columns with a case statement). Alternatively one can use format_type built-in function to do that, but it works on internal type identifiers that are visible in pg_attribute but not in information_schema. Example

SELECT a.attname as column_name, format_type(a.atttypid, a.atttypmod) AS data_type
FROM pg_attribute a JOIN pg_class b ON a.attrelid = b.relfilenode
WHERE a.attnum > 0 -- hide internal columns
AND NOT a.attisdropped -- hide deleted columns
AND b.oid = 'my_table'::regclass::oid; -- example way to find pg_class entry for a table

Based on https://gis.stackexchange.com/a/97834.