Questions tagged [datatypes]

Specifies the type of data being stored (string, date, numeric, etc).

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Using PostgreSQL what is the difference between a smallint and a bool for storing boolean?

What is the difference between the smallint type and the bool type for storing boolean values? This question arose in the comments to a question on Geographic Information Systems Stack Exchange.
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What is the best practice when creating boolean columns in Oracle?

I faced again the serious problem, that Oracle simply doesn't have a boolean column type. I need to use char(1), or smallint, or some other. What is the best practice, how to emulate boolean values ...
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Float datatype with 2 digits after decimal point

In SQL server float datatype does not display trailing zeros after decimal point declare @num as float set @num=5.20 select @num will dispaly only 5.2 But i want it to display as 5.20 After a ...
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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 ...
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3answers
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Why is XML taking up more storage than VARCHAR(MAX)?

We have large tables storing XML data as varchar(MAX). The data is for reference/historical purposes, it's not queried. Based on what I've read, storing as XML datatype instead of VARCHAR(MAX) should ...
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544 views

Most efficient data type for a column storing numeric values between 0 and 100

On my MySQL DB I was thinking of using TINYINT (Unsigned)? Would you use Byte on SQL Server?
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1answer
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PostgreSQL SELECT primary key as “serial” or “bigserial”

I've meshed together a way to determine what the data_type is as in the data_type you use in the syntax when creating a new table based off of the PostgreSQL wiki page. If there is something wrong ...
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3answers
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Constrain a postgres timestamp to “End of day”?

Given a table named bananas and a timestamp without time zone column named end_time and some psql clients have set timezone to 'UTC' and other psql clients have set timezone to 'US/Eastern' and the ...
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Trigger doesn't run when value of a column changes from null to 1

I have this trigger: delimiter $$ create trigger tr after update on t1 for each row begin if new.col1 !=old.col1 then update t2 set col2 =1 where t2.col3=t1.col3; end if; end $$ This ...
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SQL Server BigInt vs Decimal

I need to choose a data type for SQL Server( BigInt vs Decimal) on the basis of performance and querying (10 digit number)
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Databases: are there universal datatypes?

While designing database tables (using some tool like Enterprise Architect), how do I use only 'universal' datatypes that will work with all databases when I need to switch to a different database in ...
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How to restrict sequence like ID type to C type like int64_t, uint64_t, int32_t?

In C99 I can be pretty clear about the size/domain of an integer type. When interfacing a SQL database like Oracle or Postgresql from a C program I want to create a table with integer types that ...
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what is bigger than a longblob?

the longblob is the biggest data type of Mysql. If I want to save something bigger than 4gb (longblob) how can I do?. I'm talking about Mysql v-5.+
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Mapping SQL Server integer to Oracle Datatype

Well I know, that an SQL Server integer is best represented by NUMBER(10). But sometimes I have migrate some maintenance scripts to Oracle and I wonder if I must carefully map integer to NUMBER(10) ...
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How to use default value of data type as column default?

How can I specify the default value for a column in the DDL? I was pretty sure that the following method worked a while ago: CREATE TABLE test ( col_1 CHAR(12) NOT NULL, col_2 INTEGER NOT NULL ...
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1answer
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How do you index a text column in MySQL?

If I create a table with a text column CREATE TABLE foo ( bar text ); I can't index the bar column. MariaDB [test]> CREATE INDEX foo_bar_idx ON foo ( bar ); ERROR 1170 (42000): BLOB/TEXT column ...
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How to save an interval of years in postgresql

I have to save an interval of years, like: id intervalYears 1 2014/2015 2 2015/2016 3 2016/2017 And so on. Those years are like accademic years, so the first year must be lesser then the second, ...
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1answer
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Why does Oracle store time in DATE column?

I have a table with a date column. I used JDBC to save a java.util.Date object into the table. When I run following query I get date aswell as a time value: select To_CHAR(departure_date,'DD-MM-YYYY ...
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Are mime types only for file storage? [closed]

If I have a plain-text field on a web form (not a file upload) inserting its content into my table, would it be wrong for me to set a mime type 'text' to it, or would it be safer?
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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 ...
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767 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: ...
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1answer
584 views

Why is my database 12 times bigger than inserted data?

I have a short question concerning my database size. I need to insert data in a database. Before the insert, some calculations need to be done. The point is: from 50 mb plain data (~700,000 lines), ...
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1answer
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Why does a table of varchar(255) columns take up less space than an identical table using the correct data types

I have two tables that are identical and hold the same rows of data. one uses a varchar(255) for every column of the table, the other is correctly typed for each column (using date, int, decimal etc.)...
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1answer
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Find current owner of custom data type?

In Postgresql, when I try to run ALTER TYPE x ADD VALUE y; on a custom datatype I get an error stating PG::Error: ERROR: must be owner of type x. I know this can be solved by running ALTER TYPE x ...
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Estimate large database size and speed

First I want to know how to estimate the database size regarding the biggest table it will contains. I've the following : +----------+------------------+------+-----+---------+-------+ | Field | ...
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1answer
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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 ...
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1answer
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Convert varchar column to inet

I have a table column containing IP addresses, datatype is varchar(255). I want to switch to inet datatype now. Is there a way to convert existing addresses in IP column to inet datatype? Tried: ...
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Can MariaDB or MySQL cast as bigint, getting an error: … right syntax to use near 'bigint)'?

If I want to take a string and create a table (this fails in strict mode), CREATE TABLE g AS SELECT CAST('2147483699' AS int); How do I tell it that I want a bigint type? I'll also get an int(10) ...
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1answer
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Define calculated column of BOOLEAN/TINYINT(1) type in a View? [duplicate]

I'm configuring a View which contains calculated columns that should be returning Boolean results. Here's an anonymised version of the view: CREATE VIEW `ItemView` AS SELECT Item.ID ,...
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Why does a JSON element return text when it's not text?

When I try to access a JSON element using ->>'elementName' I get a texttype. SELECT pg_typeof(x1->>'a'), jsonb_typeof(x2) FROM ( VALUES ('{"a":5}'::jsonb, '5'::jsonb) ) AS t(x1,x2); ...
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1answer
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Handling sql column with mixed varchar and float data types

We have some Excel spreadsheets with parcel numbers for properties that should be in a standard varchar format similar to: [Parcel # 1] [Building Address] 038-60-171-16-000 1750 W 4th St ...
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1answer
721 views

Low cardinality fields: integer or string

A Ticket has the statuses: new in_progress on_hold closed I could make ticket.status a string (on_hold) or an unique int(2). It is indexed. Int pros: smallest size in index Int con: low clarity ...
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1answer
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Cannot SUM datetime field in SQL Server migrated from Access

I am new here and am new to SQL Server (Express). I used the SSMA tool and it converted Access date/time fields to datatime2. The data contains duration data so there is no need for a date. I want to ...
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1answer
796 views

Use of integer instead of interval (of one type)

Our DB design presently has a interval column which will only be storing days (no other interval type) so it is making sense to use INT2 (smallint) instead of interval. Reference to documentation. ...
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2answers
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PostgreSQL: Separate tables vs single table to perserve disk space?

I have 2 tables with the below schemas with equal number of rows. When I run the SELECT relname, relpages FROM pg_class ORDER BY relpages DESC command, they show up as 23GB each even though the data ...
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1answer
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Oracle implicit parameter casting - why doesn't it always work? (ORA-06502 error)

I have a Java (Spring) app that uses Oracle 10 as DB. Some legacy code has wrong parametrization of PL/SQL procedures. For instance, some input parameters are declared as OracleTypes.VARCHAR in Java ...
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Performance considerations regarding Date Vs. Char/Number/Varchar2 in Oracle

I've been working with Oracle 11g for about 7 years and I was asked for a consulting job on a small project. The problem they had was high CPU usage (more than 90%) on a 11gR2 with Windows2008 as ...
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What data type are the numbers in a SQL Server statistics object?

Specifically I'm most interested in: The 'All density' number in the density vector Numbers in the histogram E.g. are they floats / decimals? What precision / scale / length do they have? The ...
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Overwhelmed with Sensor Data - Excel to SQL Server fails

I'm managing a lot of sensor data and need to do charting, smoothing, stats over time on the data. Currently I import the data from flat files using VBA to do ETL into Excel. The format of the data ...
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2answers
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Make custom aggregate function easier to use (accept more input types without creating variants)

Recently I wrote a custom aggregate function in postgres that would return a specific column for the row that matches the max/min aggregate using a different column. While the code in itself works ...
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Use of ANY function for multiple values

I am trying to use the ANY function of PostgreSQL to search the value from array interger type column. My SQL: SELECT * FROM company_employee_contacts WHERE corporate_complaint_type_ids ...
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1answer
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How to grant the USAGE privilege on all types?

How can I grant the USAGE privilege on ALL TYPES in a schema? For tables and functions we can use ALL TABLES IN SCHEMA schema_name, but this isn't supported for types: GRANT { USAGE | ALL [ ...
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1answer
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VARCHAR2 should perhaps be DT_WSTR when working with SSIS against a Oracle Database?

When using SSIS with Oracle database, it seems to always assume that a VARCHAR2 maps to a DT_STR. However, if my Oracle encoding is set to AL32UTF8, I should be able to store any unicode character in ...
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1answer
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Why does the behavior of array syntax differ from '(?,?)' syntax when updating a point field and that field is NULL?

I'm using PostgreSQL 9.3.5. Suppose I have the following table: CREATE TEMPORARY TABLE point_test ("name" varchar(255), "pt" point); I then insert a row, leaving pt NULL: INSERT INTO point_test (...
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1answer
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SQL Server - storing ulong as primary key

I need to store ulong values as a primary key in SQL Server. Since SQL Server doesn't have a ulong datatype (or for that matter anything unsigned), the only way to go is to have column as varbinary(8)....
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1answer
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Replace “-” with NULL with Derived Column in SSIS

I am extracting information from an excel sheet and loading it into a database. Before I load it into the database, I must transform all of the "-" in the excel sheet to NULL values. I am currently ...
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1answer
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Rich text: VARCHAR, TEXT or BLOB in MySQL

Question: In my web application (php/MySQL) I will be saving rich text. This may be anything from a couple words to several pages length essay. I’m sure I could get away with using VARCHAR, TEXT or ...
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1answer
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Is 'internallength' always useful in custom type definition in Postgres?

In our database we use a custom type to store 3D locations: CREATE TYPE float3d AS ( x real, y real, z real); In many examples I see INTERNALLENGTH used as a parameter with the definition of ...
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1answer
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How to compare (in MySQL) a DATETIME value to a TIMESTAMP value?

I'm trying to understand how to compare a DATETIME value (ostensibly inserted as GMT) and a TIMESTAMP value (automatically generated at INSERT time). As I understand it, the DATETIME is set to ...
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1answer
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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 ...