Questions tagged [datatypes]
Specifies the type of data being stored (string, date, numeric, etc).
479
questions
0
votes
2answers
47 views
Choice between two antipatterns: Overdesign versus Over-optimization
Sometimes I need to keep state, like an IsVerified flag.
There are two options:
boolean (or bit)
Advantage: smallest and fastest
...but in theory "over-optimization" and thus a bad argument.
...
0
votes
1answer
13 views
Postgres custom type with constraints
I was wondering if it were possible (and/or desirable) to create custom types with constraints on the values. Say I have a custom type for height/width/length:
CREATE TYPE dimensions AS (w float, h ...
2
votes
1answer
44 views
How to find type mismatches (implicit conversion) between sprocs and tables?
I have a sproc that has these lines
DECLARE @newTimestamp datetime = CURRENT_TIMESTAMP
UPDATE dbo.Accounts
SET Modified = @newTimestamp
However, in the Accounts DB, we have this
[Modified] ...
1
vote
0answers
61 views
How to estimate the nonclustered index size before its creation?
I created two scenarios and expected to see the same result but the results were noticeably different. I would like to know where I did wrong.
Scenario 1
Create table mytable1 with clustered index and ...
1
vote
1answer
26 views
Help understanding behavior of try_cast() with numeric strings
Erwin made a great, generic try_cast function for postgres (copied below). I'm interested in using it for an EAV schema where attributes are stored with a type field. I can use a similar function (...
0
votes
1answer
31 views
How does MongoDB Treat Mixed Types?
I'm messing around with mongodb and noticed I can create mixed data types.
db.getSiblingDB("bermuda").getCollection("test").insertOne({
"profile": {
"t1&...
1
vote
1answer
70 views
Is there any performance implication from using varchar(max) over varchar(n) in cast/convert?
Consider the following expression, which truncates (does not round) the milliseconds from a date-time value:
declare @now datetime2 = sysdatetime();
select @now;
select convert(datetime2, convert(...
0
votes
1answer
24 views
Postgres metadata: get a list of all MATERIALIZED VIEW columns, with data type, INCLUDING array columns
I need to get metadata about all MATERIALIZED VIEW columns, including their data type. I can do this with this query:
SELECT
trim(leading '_' from pg_type.typname) as data_type,
pg_namespace....
2
votes
2answers
58 views
Convert postgres varchar[] to text[] without downtime
As I discovered in researching this question, converting a column from varchar(100)[] to text[] requires a table rewrite and rebuilding indexes.
Is there a way to manage this conversion without the ...
3
votes
1answer
45 views
Postgres varchar(100)[] -> text[] column conversion
I need to change a column type from varchar(100)[] to text[]. The table has >100M rows and heavy write load, so I'd like to avoid taking an access exclusive lock and rewriting the index. I saw in ...
0
votes
1answer
31 views
Enforcing same type for two columns
Is there any method of constraining column types between tables in MariaDB?
When creating foreign keys column types have to match. I would like to make sure two or more columns always stay the same ...
3
votes
2answers
408 views
Why database has char data type when varchar is more efficient?
I understand the basic difference between CHAR and VARCHAR datatype that CHAR takes up fixed length whereas VARCHAR takes up space based on the content being stored.
But if VARCHAR is so efficient in ...
1
vote
2answers
90 views
Does SQL Server's is_nullable mean anything at all?
SQL Server has a type flag called is_nullable you can see it on sys.types. Currently, (SQL Server 2019) it's only set to FALSE two types, sys.timestamp and sys.sysname. On sys.timestamp this type ...
-1
votes
3answers
168 views
How can I cast to a user-defined type in SQL Server?
SQL Server provides an ability to create a user defined type with CREATE TYPE
CREATE TYPE foo FROM int NOT NULL ;
However, there is no mention how I construct a value with that type. Is this of use ...
0
votes
2answers
57 views
What is the SQL Server equivalent of pg_typeof(), how can I get the type of a column returned in a result set?
Using PostgreSQL, I can use pg_typeof(exp) like
SELECT pg_typeof( cast(1 AS int) );
SELECT pg_typeof(x), x FROM foo;
And get back the result (integer in the case of the first example). Is there a SQL ...
4
votes
3answers
229 views
Why do subsequent unmet conditions in my CASE statement affect my return data type?
I have the following variables and CASE statement:
DECLARE @DATE_VALUE VARCHAR(20) = '4/29/2021'
DECLARE @CONVERT_CODE VARCHAR(1) = 'I'
SELECT CASE @CONVERT_CODE WHEN 'I' THEN DATEDIFF(day, '04/21/...
3
votes
1answer
216 views
What's the difference between equality (=) and inequality (<>) on BIT field in SQL Server?
Is there difference between WHERE [BitField] = 1 and WHERE [BitField] <> 0?
They seem logically equivalent.
SQL Server, however, disagrees and creates slightly different execution plans. (Which ...
1
vote
1answer
65 views
How do I debug Postgres' join strategy?
In the process of optimizing a Postgres query, I ran into a situation where two equivalent, simple queries execute in very different amounts of time. While I can't provide a reproducible example for ...
2
votes
2answers
281 views
What are the various Informix column data types?
I am writing a query where I need to know if a column is of the "BLOB" type of column. According to this documentation 41 is the number for "BLOB" types of columns, in general. ...
0
votes
2answers
38 views
Add a column with name as a result from a SELECT
I'm using PostgreSQL on my project and I have a Spring Boot Application that uses Flyway to create everything on my Database. I need to create a column that its type is based in a row on other table.
...
0
votes
1answer
69 views
Converting DATE and TIME integers to timestamp
I am trying to get a timestamp by combining date and time columns in my PostgresQL database and am running into errors. Here is what I have:
+-----------+-----------+
| StartDate | StartTime |
+-------...
5
votes
2answers
788 views
How to change an incorrect datatype for a birth date field from VARCHAR to DATE
I made a mistake when creating my users table with a birthdate field and instead of putting the DATE datatype, I put a VARCHAR!
So now my users table looks like this:
CREATE TABLE IF NOT EXISTS users
...
1
vote
3answers
144 views
Implicit conversion: when does it hurt performance a lot?
I know that when data types are the same it is good and it hurts performance when they are not.
But sometimes it seems to have very little impact and basically a waste of time to fix it. Other times ...
0
votes
1answer
15 views
Why does mySQL automatically add display length to numeric values when adding zerofill property
I am trying to understand better how the data types are processed by the MySQL system, so I created a table in the following way:
# Field, Type, Null, Key, Default, Extra
test1, tinyint(3) unsigned ...
0
votes
2answers
82 views
How to change the datatype of column without deleting it indexes; [closed]
I am looking for changing the datatype of a field from nvchar(20) to nvchar(MAX), but it retains the below message.
my questions here:
Deleting the index will affect on the data?
Can I restore the ...
0
votes
1answer
19 views
Need help identifying how to make a function selectable using table() clause and a custom data type
I would like to be able to run the following code to select records:
Desired Syntax
select * from table(my_new_package.get_data(123))
I have been successful in creating code that compiles, but I am ...
0
votes
0answers
65 views
Oracle database, convert XMLTYPE table from basicfile lob to binary xml
Trying to import an Oracle EBS database (currently in a 19c staging database) into 19c Autonomous Data Warehouse, which won't accept XMLTYPE tables with "STORE AS BASICFILE LOB", but will ...
5
votes
1answer
224 views
Why is changing data types not effecting the database size?
I have a table with four columns and ~660 million rows. Two of the columns are bigint although they are not really required to hold any content that could not also fit into int. So as a test I changed ...
0
votes
2answers
47 views
convert date in string format to date datatype sql [duplicate]
I have values in a column named Date as a nvarachar data type in the form of mmddyy and want to convert the values to a date datatype in the form of yyyy-mm-dd. What sql colde can I use to convert the ...
1
vote
1answer
119 views
Store Decimal values without Trailing Zeros
I am using SQL Server 2008 R2 version.
Is there any method to store decimal value in SQL without extra trailing zeros(like Float data type format).
I have created a column with decimal data type with ...
1
vote
1answer
248 views
What value should I choose as length for timestamp without timezone in PostgreSQL?
I'm currently setting up a database to populate it with big data. All the data I get comes from Valve's Steam Web API. Therefore, as all timestamps are returned in Unix timestamps, I cannot directly ...
0
votes
2answers
263 views
Materialized view with FAST refresh on remote table: How to include a GEOMETRY column?
I want to create a fast refresh materialized view (18c) on a remote table. The MV would also have a GEOMETRY column.
Options for the GEOMETRY column datatype include:
ESRI's proprietary ...
2
votes
1answer
35 views
Best practices for integer key types - mixed or all the same integer type?
I am designing a postgres database for scientific data. It has about 30-40 tables, many of which are lookup tables with less than 10 records. The bulk of the data are concentrated in just a few tables ...
0
votes
0answers
180 views
Better option to store latitude and longitude on Postgres
I'm adding a GIS module to my Proyect, then I need o store latitude and longitude into my Postgres Database(table target has 500,000 registers by now).
For example:
latitude = 40.767504
langitude = -...
0
votes
2answers
88 views
Should Postgres function return/coerce numeric scale/precision?
The following function returns two generic numerics, not the numeric(20,10) I think I'm specifying in the function return definition. This is unexpected (by me). Is there a way to ensure the function ...
0
votes
0answers
56 views
Is there, or isn't there a boolean data type in SAP ASE?
ALL,
According to the Embedded SQL/C manual the DBMS supports the boolean type, to which CS_BIT is mapped on the application side.
However, when I tried to use it inside CREATE TABLE() statement, I ...
0
votes
3answers
246 views
char or smallint for a column with numeric codes?
I have columns in my application that have values that always have 4 digits, e.g. '0100' or '1230'. One of examples could be Merchant Category Code.
For the time being, I have set the type of this ...
1
vote
1answer
46 views
What is most efficient way to store one or two chars?
In Postgres table with ca million rows I have a column bookingtype (character varying(20)), which default value is null and besides that it may have 7 distinct values (1-2 chars). Current situation:
...
1
vote
0answers
47 views
How to store values of different entity types in database?
I created the schema of ref_entity and ref_entity_type:
create table ref_entity (
id serial primary key,
name varchar(255) NOT NULL,
type_id integer,
code varchar(255)
constraint FK_REF_ENTITY_TYPE ...
0
votes
1answer
221 views
Is there any way in Postgres to parameterise a procedure for sort order column, when the columns are of different types?
I am trying to write a function which does (some complex stuff) and returns the results in different orders based on a parameter.
A simplified version would look something like this:
CREATE OR REPLACE ...
5
votes
1answer
304 views
DATEADD and DATEPART with milliseconds yields strange results
I have a table containing the date in unix time and a separate milliseconds field. I now try to create a date from the two fields for later calculation (e.g. filtering on a time range). After adding ...
-1
votes
1answer
114 views
JSON vs Record/Struct type in a DB
It seems like some databases have implement a Record/Struct type and others have implemented a Json/Jsonb type to handle nested data structures. A few examples being:
BigQuery Struct
CockroachDB ...
1
vote
1answer
677 views
What is the SQL Server equivalent for Oracle character set AL32UTF8?
While porting data from oracle to Azure sql database I am facing the following issue where, empty data in Oracle is converted as ➞➞➞ in SQL Server
Pic1: Data as in Oracle DB;
Pic2: Data as in Sql ...
1
vote
1answer
279 views
Oracle: Inserting into table error - either duplicate column name or invalid datatype
I'm trying to insert data from an external table.
INSERT /*+ ignore_row_on_dupkey_index ( consruct ( construct_id ) ) */
INTO construct
(construct_id,
n_term ,
enz_name,
...
0
votes
0answers
11 views
BIT VARYING internals
I Have a table called IP_Block in which I created two columns
ID of type Bit Varying(32) as PK
IP Bloc of type CIDR
the construction of the ID is the following :
For example for the block 1.0.0.0/8 ...
0
votes
1answer
857 views
Storing Hex Colors in a column in Postgres
I want to store Hex color codes in a column in my Postgres database. I would like to put a restriction on the column to ensure it has the format of being a hex color (Example: #FFAA00)
Some Example of ...
0
votes
0answers
85 views
Best field type for cryptocurrency big numbers?
I'm using PostgreSQL for my cryptocurrency exchange database, the question is: for saving currency amount (numbers) with their precision (like 323232323232323.45454545 ~ 23 digit + 1 dot: 15 digit ...
0
votes
0answers
340 views
getting BIGINT UNSIGNED value is out of range for integer columns
Why am I getting a BIGINT out of range error when summing 2 integer values that should be within range?
SELECT
*,
numberSent - cd
FROM
(SELECT
e.id,
e.numberSent,
COUNT(d.id) cd
...
0
votes
2answers
54 views
Question on datatypes for photo app
I am working on a relational database design for a photo organising app, and as I have mentioned before, am very new to databases. I need to include exposure, aperture value and focal length. The ...
0
votes
1answer
17 views
Sqlite Affinity for hashvalues with certain size
I must store many SHA256-values in a sqlite-database and now i wonder which sqlite-affinity would be the correct one. SHA256-values have an output-length of 256bit=32byte. I am looking for an sqlite-...
