Questions tagged [datatypes]
Specifies the type of data being stored (string, date, numeric, etc).
417
questions
0
votes
2answers
80 views
VARCHAR vs DATETIME
What is the reason for using VARCHAR datatype on a column storing values in date and time 2020-01-01 11:04:37 instead of using DATETIME datatype in SQL database table?
-1
votes
1answer
30 views
Convert DATETIME [closed]
I have to convert datetime:
2011-10-16 11.12.06
to
2011-10-16 11:12:06
I tried out:
SELECT CONVERT(VARCHAR(29), '2011-10-16 11.12.06', 120)
but still its returning '2011-10-16 11.12.06'.
...
14
votes
4answers
3k views
What is the right data type to store only -1 0 and 1 in postgres column?
I want to store only 3 states in a column (if it was 2, I would use a boolean)
I considered using an ENUM('up', 'down', 'none') but it seems ENUMs take some significant space
Is there a better way to ...
2
votes
0answers
37 views
Postgres 11: fastest way to convert a small list of numbers to text (to be used as NOTIFY payload)
I am on Postgres 11.5 and in a trigger function I issue one or more pg_notify calls for each row modified in the transaction. The most common payload is a list of 12 float numbers, representing two ...
3
votes
2answers
81 views
How to store values that include numbers and strings? Example: 1.25, trace, not applicable, etc
I created a database for nutritional table information. This database have values like carbohydrates, protein and fats of a food (there is a total of 28 fields).
The problem is that there are special ...
5
votes
2answers
203 views
default permissible datatype conversion matrix
Today I wanted to define a uuid of value 00000000-0000-0000-0000-000000000000. Being a SQL Server man, I'd usually...
select cast(0x0 as uniqueidentifier);
...but I'm in postgres world now so I ...
1
vote
1answer
31 views
Bit map of yes/no answers: Should I store it as binary, blob, varchar, or int?
I am developing a web app in Laravel where I have to ask users a set of Yes/No questions and save the answers in the database. I thought that I should try and save all answers in binary rather than ...
1
vote
1answer
30 views
Numeric data-type for integers
I need to store exact sums of bigint columns in a summary table. So I must use data type numeric for those columns.
Now I am wondering if setting the scale to 0 in this case makes sense (e.g. maybe ...
1
vote
3answers
69 views
Having md5(NULL) return a non-NULL value in postgresql
I have a table with the structure (content_md5 UUID, content TEXT), where I'd like to use content_md5 (which is the value of md5(content)) as the primary key, and use it as a foreign key in other ...
3
votes
2answers
77 views
Is DEFAULT NULL and 'nullable value without default' completely the same?
ALTER TABLE test_table ADD COLUMN a DEFAULT NULL;
vs.
ALTER TABLE test_table ADD COLUMN a;
Both columns will set NULL if column a is not specified.
As far as I know, if I add a column into a table ...
0
votes
0answers
289 views
Typeorm: How to make composite key in one table as foreign key in other table
I'm using Typeorm JavaScript not Typescript for PostgreSQL in Nodejs application. I have a two tables:
Resource
Passenger
In Resource Table I have id and type both are primary key and act
as ...
2
votes
2answers
388 views
Postgresql: Cast row to type
I read: Use composite type to create new table
I have a table called locations, e.g. representing objects with lat. and long. coordinates.
In another table, I declared a column of type locations (...
4
votes
1answer
522 views
Postgresql numeric and decimal is automatically rounding off
CREATE TABLE IF NOT EXISTS ttable (
tcol decimal(9,7)
);
insert into ttable(tcol) values(17.4604786);
the value is getting stored as 17.46
Happens the same if I use decimal/numeric type
I am ...
1
vote
1answer
83 views
Postgres numeric type overflow after 1023 bisection of 1
i am testing the numeric type in postgres according the precision and scale i declared the numeric type with (1000,900) which gives me 900 digits decimal points but when i test it by inserting and ...
0
votes
1answer
39 views
PostgreSQL CREATE TYPE using multiple relations?
I'm becoming familiar with PostgreSQL's ability to define a data type https://www.postgresql.org/docs/current/sql-createtype.html using CREATE TYPE syntax.
It appears to me that this type does not ...
-1
votes
1answer
32 views
how to get content from a TEXT column in mysql? [closed]
maybe dumb question but if I have a table with a MEDIUMTEXT column how do I query that table and see what the actual content is? eg SELECT text FROM PRIMARY_TEXT WHERE id = 1. What I get back now is [...
2
votes
1answer
61 views
Change column datatype without rewrite when data remains unchanged
For example:
timestamp(tz) to int8
date to int4
json to text
The raw data is unchanged, and the only difference is how that data is handled. So it should be possible to change back and forth cleanly ...
0
votes
1answer
29 views
Handling MySQL length=22 and decimals=31
I'm using MySQL's C api to determine the maximum possible value that can be stored in a specific field.
I have the following table:
CREATE TABLE test (
f1 double(4,2),
f2 double
)
When I ...
0
votes
0answers
19 views
Proper way to store permissions (datatype)
I'm modeling a MySQL database and it has a users table with the columns:
username
passhash
permissions
The access crontrol will be made on programming level (NodeJS).
Each user may have a different ...
6
votes
1answer
174 views
Is it safe to use Strings instead of SqlStrings for CLR function input parameters?
I have a CLR scalar UDF implemented through C# code. I've noticed that using the String data type for input parameters significantly improves performance compared to the SqlString data type. In ...
1
vote
1answer
32 views
Designing Calendar table - datatypes
I'm in the process of designing the Calendar table. I took some inspiration from Database design book by Louis Davidson.
What I'm confused about are the data types.
Example:
MonthName varchar(10) ...
2
votes
2answers
165 views
Generic type functions in T-SQL
Consider the following function
CREATE FUNCTION dbo.SafeDivide
(
@a numeric,
@b numeric
)
RETURNS numeric
AS
BEGIN
RETURN CASE
WHEN @b = 0
THEN 0
...
1
vote
1answer
43 views
Why does Oracle consider a larger number to be smaller? [closed]
For some reason when I try to do greater than or less than, it says that 100 is less than 2. I think it's only reading the first digit when it determines the greater/less value. Not sure why or if its ...
2
votes
0answers
191 views
Storing GTIN/EAN values with PostgreSQL. Which data type to use?
I am building a product database and I need to store GTIN/EAN (Global Trade Item Number/European Article Number) values. Probably except GTIN-14 as it does not seem to be used at retail sales? I read ...
0
votes
0answers
238 views
MySQL (MariaDB) - “Data too long for column” for a very short value, not reproducible elsewhere
I have a table logs with a column info - the type is text. I get an error running the following query:
insert into logs (date_time, info, log_code, company_id,
updated_at, created_at) values ('...
7
votes
2answers
690 views
how to create a data type and make it available in all Databases?
If I create a stored procedure in the master database, and I want to execute it from any of my databases I just follow this link:
Making a Procedure Available in all Databases
that give me this code ...
1
vote
1answer
1k views
How is TINYINT(1) converted to BOOL/BOOLEAN?
I can understand that if you UPDATE a TINYINT(1) column and pass a value of 1 or 0 it will convert it to TRUE or FALSE, respectively.
I'm just confused on what happens when you UPDATE the column ...
5
votes
2answers
923 views
Do varchar(max), nvarchar(max) and varbinary(max) columns affect select queries?
Consider this table:
create table Books
(
Id bigint not null primary key identity(1, 1),
UniqueToken varchar(100) not null,
[Text] nvarchar(max) not null
)
Let's imagine that we have ...
2
votes
1answer
288 views
Implicit Conversion of VARCHAR Column to NVARCHAR does not cause expected table scan
Given the following script, I can see implicit conversion and Data type precendence have a negative impact on a query plan
-- create objects
CREATE DATABASE ConvertTest
GO
USE ConvertTest
GO
CREATE ...
-1
votes
1answer
144 views
MySQL - Optimize a table which has mostly text data type
I recently faced some performance issue on a CMS based application. I can somehow fix other tables. But Im not able to optimize the table which has 40+ columns and 10 columns are having text as the ...
3
votes
1answer
61 views
Definition of indexing, datatype configuration, and DBMS for SHA3-256 hashes
I am designing a system within which I will need to be able to search a database using a file or string SHA3-256 hash.
For example the hash of test is
...
0
votes
1answer
91 views
Appropriate column type(s) for dates and dynamic pricing data
What is the appropriate column(s) type(s) (trying to be database agnostic, but realize that could play into the answer) to store a months worth of pricing data (i.e. could be the daily hotel rate, etc....
1
vote
1answer
48 views
Datetime hourly precision
What would be the best to store date + hour + timezone in SQL? i dont need a higher precision (minutes, seconds, ms..) the primary reason for this is to reduce memory use and calculation time on big ...
1
vote
1answer
34 views
Different categories of missings
Most database systems can represent missing values, typically as "Null" or something similar. But what if I want to represent different categories of missing data?
For categorical data, this is ...
4
votes
2answers
218 views
Different syntax to add/substract interval
Till now I used the following syntax to add an interval to a timestamp:
select now() + '5 year';
This worked fine till I tried to subtract the interval which results in a syntax error.
invalid ...
3
votes
2answers
851 views
Postgres jsonb vs composite type performance differences
What considerations are involved in choosing between a jsonb column and a composite type column of the same structure?
For example, consider a column like that used in the Postgres documentation:
...
0
votes
2answers
1k views
best column type for hashed data in mysql
In my use case I have a table with a column containing hashed (sha256) IDs. I wonder which data type is better considering that It must be unique and I need to search on it.
The sha algorithm ...
2
votes
0answers
72 views
Non-standard number data types in Oracle
I'm not sure that this question belongs to this StackExchange.
I've asked this question on StackOverflow:
Besides the "usual" number data type where precision is greater then scale there are ...
-1
votes
1answer
25 views
Creating blog fresh tables from old tables [closed]
I am re-creating a database structure from old tables. New tables should be optimized and easy to understand.
In old database the developer used video table name for storing video blogs. However I ...
2
votes
0answers
51 views
How costly is changing column datatype in PostgreSQL?
I'm currently evaluating PostgreSQL for an app we are developing which comes with a weird usecase. We want to allow clients to create new fields which in turn will create new columns in a client-...
1
vote
1answer
82 views
Why does ENCODE on BYTEA not seem to have any performance impact?
I am working on a scenario to store strings in hex format of fixed length 64 to database. Obviously the choices are BYTEA and CHAR(64).
Initial thought was to enforce a valid hex string storing it ...
1
vote
3answers
817 views
Find max content length of column of particular table from entire SQL server
I have a 3 SQL server: Server1,Server2 and Server3.
Each search has approx 50-60 databases.
In a particular database there is a table name table1 and it has a column named column1 with datatype ...
3
votes
1answer
194 views
Datatype for a Persisted Computed Column? Should I Convert/Cast When Creating It?
What is the Datatype for a Persisted Computed Column?
(a) Does SQL Server automatically infer it?
(b) Also is better to cast it as a datatype, so SQL does not spend time to find what data type it ...
1
vote
0answers
63 views
Used a CAST function ,still IMPLICIT Conversion warning in Execution Plan
I know that IMPLICIT Conversion warnings occur when the SQL server has to convert a value to a another datatype to do some processing.
I am getting this warning in an execution plan and when i checked ...
2
votes
1answer
56 views
Converting a string to an object reference
Sometimes I end up in a position where I have a string version of my object reference like so:
'server.database.schema.table'
And I need to use it as an actual object reference:
'server.database....
5
votes
1answer
168 views
Question regarding decimal arithmetic
I think my understanding of precision vs scale might be incorrect as the following example produces values that do not make sense to me. decimal(32, 14) rounds the result to 6 decimal places, while ...
10
votes
2answers
2k views
When `nvarchar/nchar` is going to be used with SQL Server 2019?
With SQL Server 2019 Microsoft introduces UTF-8 support for CHAR and VARCHAR data types and says:
This feature may provide significant storage savings, depending on the
character set in use. For ...
6
votes
2answers
481 views
Is there a way to partially initialize a TYPE?
I have created a custom type:
CREATE TYPE my_type as(name text, street text, location text);
Initializing such a type is easy:
SELECT ROW('a', 'b', 'c')::my_type;
I am wondering if there is an ...
7
votes
1answer
3k views
What is the data type 'name' in PostgreSQL
I can not find any references to the data type 'name' in the postgres documentation but I am seeing it as a data type on the pgagent.pga_jobstep table for the column 'jstdbname'. The udt_name is also ...
2
votes
4answers
12k views
Converting columns from NVARCHAR to VARCHAR
I have several large tables with many NVARCHAR(MAX) columns. This database is only for US use and I don't think there are any foreign characters or letters in any of the columns, so I wanted to look ...
