Change timestamp
Author: w | 2025-04-24
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Timestamp that won't change
Lfete (Peter´s Blog). Спасибо за содействие!Перевод на Немецкий (Инсталлятор) язык выполнил Maaster (Phillipp Arnold) (Maasters Website). Спасибо за содействие! 2009/08/21Версия:1.03Изменения: - The Window is now resizable. - Added "Secs" and "Mins" for offset menu. - Added "Refresh" button in "View & Copy" mode. - Revised some Japanese texts. 2009/08/09Версия:1.02Изменения: - Added new function "Synchronize To: The Newest File" and "Synchronize To: The Oldest File" in mode "Change Multiple File(s) / Folder(s) at Once". - Changed background color. - Fixed a bug in which "Specific" in mode "Change Multiple File(s) / Folder(s) at Once" was writing wrong time when "Synchronize To: Current Time" was checked. - Added Spanish language support.Перевод на Испанский язык выполнил Adrian from Spain. Спасибо за содействие! 2009/07/21Версия:1.01Изменения: - Fixed a bug in which only single file was being processed when you drop even multiple files in "Change Multiple Files / Folders at Once" mode. - Fixed some bugs in its installer. 2009/07/15Версия:1.00Изменения: - Moo0 TimeStamp 1.00 has been released.------------------------------------------ (Pages for Non-Frame Browser) ------------------------------------------[Moo0 - Полезные бесплатные программы для Windows (not MooO)]:Moo0 Список программMoo0 Список Web ApplicationEnglish): TimeStamp (Free) - Modify File Timestamp | free timestamp software, time stamp software, timestamp editor, timestamp software, timestamp program, timestamp modifier, timestamp changer, timestamp download, change file timestamp, change photo timestampعربي): الطابع الزمني (مجاني) - قم بتعديل ملف الطابع الزمني | برنامج الطابع الزمني مجانا, برنامج الطابع الزمني, برنامج الطابع الزمني, برنامج الطابع الزمني, برنامج الطابع الزمني, معدل الطابع الزمني, مغير الطابع الزمني, الطابع الزمني تحميل, تغيير الطابع الزمني الملف, تغيير الطابع الزمني الصورةБеларускі): TimeStamp (Бясплатна) - Зменіце пазнаку часу файла | свабоднае праграмнае забеспячэнне пазнакі часу, час праграмнае забеспячэнне марка, рэдактар часовай пазнакі, пазнакі часу праграмнае забеспячэнне, пазнакі часу праграма, Мадыфікатар часовай пазнакі, пазнакі часу змены, пазнака часу загрузкі, змяненне файла пазнака часу, змяненне фота пазнака часуDansk): TimeStamp (Gratis) Free cleaner, cleaner free download, moo0 disk cleanerFile Monitor (Free) - Monitor file access easily | file monitor, filemonitor, monitor file access, file access monitor, file activity monitoring, file-monitor, file access monitoring software, windows file monitor, moo0 file monitor, file monitor windows 7File Shredder (Free) - Erase private files permanently | file shredder, file shredder portable, moo0 file shredder, data shredder, file eraser, erase private file, erase private phote, prevent data recovery, protect private data, fileshredderHash Code (Free) - Calculate / Verify Hash Code | hash code reader, hash code calculate, hash code, easy hash download, hash number, software hash, hashcode download, download hash code, code hash, what is a hash codeTimeStamp (Free) - Modify File Timestamp | free timestamp software, time stamp software, timestamp editor, timestamp software, timestamp program, timestamp modifier, timestamp changer, timestamp download, change file timestamp, change photo timestampColor Picker (Free) - Pick Color from Screen | pickcolor, color picker download, html color picker, color picker chrome, pick color, color picker windows, chrome color picker, windows color picker, html colour picker, colorpickerFont Viewer (Free) - Quickly Find Fonts of your Needs | font viewer, fontviewer, font viewer portable, free font viewer, font viewer free, fonts viewer, windows font viewer, moo font, font viewers, font viewer downloadImage Colors (Free) - Convert Images into Various Color Tones | image colors, change color software, adjust color software free, change image colors, photo colouring software, change photo colors, image color changer, different color tones, change color tones, adjust color tonesImage Converter (Free) - Convert Image Files Easily | png to ico, image converter, convert png to ico, jpg to ico, ico converter, picture converter, ico to png, convert to ico, png to ico converter, jpg to gif converter free downloadImage Sharpener (Free) - Easily Sharpen/Blur image files | image sharpener, photo sharpening software free, photo sharpener, photo sharpening software, picture sharpener, image sharpening software, photo sharpening, picture sharpening software, free photo sharpening software, image sharpening software freeImage Resizer (Free) - Convert Image Sizes Easily | imagesizer, sizer images, image sizer, sizer image, picture size converter, image size converter, moo image, imagechange file timestamp, express timestamp toucher
It is a special version of "Timestamp Camera" for Instagram, It has been optimized for Instagram. You can add date and location text watermark to photo and video and share to Instagram, so your friends will know when and where it exactly happened.Main features● Add current time and location when recording or capturing, you can change time format or select the location around easily. Timestamp Camera is maybe the only App that can record video with the time accurate to second.- Support 20 timestamp format- Support change font, font color, font size- Support set timestamp in 6 positions: top left, top center, top right, bottom left, bottom center, bottom right- Support auto add location.- Support change timestamp opacity● Support display custom text and emoji on camera. For example, you can input "Good day at the zoo"● Support portrait and landscape● Support change resolutionPlease mail us [email protected] if you have any problem or suggestions. Thank you.. Download Change Timestamp [EN] Scarica Change Timestamp [IT] Change Timestamp indir [TR] Pobierz Change Timestamp [PL] Tải xuống Change Timestamp [VI] 下载Change Timestamp [ZH] ダウンロードChange Timestamp [JA] Unduh Change Timestamp [ID] Download do Change Timestamp [PT]Import missing timestamps, and change files timestamps
NOTE: This vulnerability no longer affects Ethereum mainnet as of the Proof of Stake merge. Read moreThe timestamp of a block, accessed by block.timestamp or alias now can be manipulated by a miner. There are three considerations you should take into account when using a timestamp to execute a contract function.Timestamp ManipulationIf a timestamp is used in an attempt to generate randomness, a miner can post a timestamp within 15 seconds of block validation, giving them the ability to set the timestamp as a value that would increase their odds of benefitting from the function.For example, a lottery application may use the block timestamp to pick a random bidder in a group. A miner may enter the lottery then modify the timestamp to a value that gives them better odds at winning the lottery.Timestamps should thus not be used to create randomness. See Weak Sources of Randomness for Chain Attributes.The 15-second RuleEthereum's reference specification, the Yellow Paper, doesn't specify a limit as to how much blocks can change in time, it just has to be bigger than the timestamp of its parent. This being said, popular protocol implementations reject blocks with timestamps greater than 15 seconds in the future, so as long as your time-dependent event can safely vary by 15 seconds, it may be safe to use a block timestamp.Don't use block.number as a timestampYou can estimate the time difference between events using block.number and the average block time, but block times may change and break the functionality, so it's best to avoid this use.SourcesConsensys Smart Contract Best Practices - Timestamp Dependence (Attacks)Consensys Smart Contract Best Practices - Timestamp Dependence (Development Recommendations) '2016-03-26 10:10:10-05:00'), (2, TIMESTAMPTZ '2016-03-26'); icon/buttons/copy > SELECT * FROM timestamps; a | b+---+---------------------------+ 1 | 2016-03-26 15:10:10+00:00 2 | 2016-03-26 00:00:00+00:00(2 rows)Create a table with a TIMESTAMP-typed column, with precision icon/buttons/copy > CREATE TABLE timestamps (a INT PRIMARY KEY, b TIMESTAMP(3)); icon/buttons/copy > SHOW COLUMNS FROM timestamps; column_name | data_type | is_nullable | column_default | generation_expression | indices | is_hidden--------------+--------------+-------------+----------------+-----------------------+-----------+------------ a | INT8 | false | NULL | | {primary} | false b | TIMESTAMP(3) | true | NULL | | {primary} | false(2 rows) icon/buttons/copy > INSERT INTO timestamps VALUES (1, TIMESTAMP '2020-03-25 12:00:00.123456'), (2, TIMESTAMP '2020-03-26 4:00:00.123456'); icon/buttons/copy > SELECT * FROM timestamps; a | b----+-------------------------------- 1 | 2020-03-25 12:00:00.123+00:00 2 | 2020-03-26 04:00:00.123+00:00(2 rows)To change the precision level of a column, you can use an ALTER COLUMN ... SET DATA TYPE statement: icon/buttons/copy > ALTER TABLE timestamps ALTER COLUMN b SET DATA TYPE TIMESTAMP(4); icon/buttons/copy > SHOW COLUMNS FROM timestamps; column_name | data_type | is_nullable | column_default | generation_expression | indices | is_hidden--------------+--------------+-------------+----------------+-----------------------+-----------+------------ a | INT8 | false | NULL | | {primary} | false b | TIMESTAMP(4) | true | NULL | | {primary} | false(2 rows)When changing precision level, TIMESTAMP can be changed to TIMESTAMPTZ, and TIMESTAMPTZ can be changed to TIMESTAMP: icon/buttons/copy > ALTER TABLE timestamps ALTER COLUMN b SET DATA TYPE TIMESTAMPTZ(5); icon/buttons/copy > SHOW COLUMNS FROM timestamps; column_name | data_type | is_nullable | column_default | generation_expression | indices | is_hidden--------------+----------------+-------------+----------------+-----------------------+-----------+------------ a | INT8 | false | NULL | | {primary} | false b | TIMESTAMPTZ(5) | true | NULL | | {primary} | false(2 rows)Note:If a non-default precision level has already been specified, you cannot change the precision to a lower level.In this case, the b column, which is of type TIMESTAMPTZ(5), cannot be changed to a precision level below 5: icon/buttons/copy > ALTER TABLE timestamps ALTER COLUMN b SET DATA TYPE TIMESTAMPTZ(3);ERROR: unimplemented: type conversion from TIMESTAMPTZ(5) to TIMESTAMPTZ(3) requires overwriting existing values which is not yet implementedSQLSTATE: 0A000Convert a TIMESTAMP to seconds since epoch icon/buttons/copy Convert a TIMESTAMP to milliseconds since epoch icon/buttons/copy SELECT (now()::float*1000)::int;Convert a TIMESTAMP to microsecondsHow to change timestamp of SQLITE DB to local timestamp
This datatype is also known as "rowversion", and the original name is really unfortunate. A timestamp column is automatically updated whenever a row is updated, and the value is monotonically increasing in the database. There is absolutely no relation to date and time. The main purpose of timestamp is to implement optimistic concurrency. The client reads a row from the database gets the timestamp value from the database and sends it back on UPDATE. The UPDATE operation includes a condition on timestamp in the WHERE clause, and if the timestamp value has changed since the client read the value, the update is not performed - and the update that came in-between is not lost. timestamp/rowversion does not seem to be that popular these days, but I have worked with a system where have many of these columns for exactly this reason. Because it is monotonically increasing, some people also use it to find the most recently changed rows in a table, but this is not what it is designed for, and it does not work well in high-concurrency environment. SQL Server offers better features for this purpose, for instance Change Tracking.How to Change the Timestamp of Any
On this page The TIMESTAMP and TIMESTAMPTZ data types store a date and time pair in UTC.VariantsTIMESTAMP has two variants:TIMESTAMP presents all TIMESTAMP values in UTC.TIMESTAMPTZ converts TIMESTAMP values from UTC to the client's session time zone (unless another time zone is specified for the value). However, it is conceptually important to note that TIMESTAMPTZ does not store any time zone data.Note:The default session time zone is UTC, which means that by default TIMESTAMPTZ values display in UTC.The difference between these two variants is that TIMESTAMPTZ uses the client's session time zone, while the other simply does not. This behavior extends to functions like now() and extract() on TIMESTAMPTZ values.Note:A time zone offset of +00:00 is displayed for all TIME and TIMESTAMP values, but is not stored in the database.You can use the timezone() and AT TIME ZONE functions to convert a TIMESTAMPTZ into a TIMESTAMP at a specified timezone, or to convert a TIMESTAMP into a TIMESTAMPTZ at a specified timezone.Explore the differences of TIMESTAMP and TIMESTAMPTZ in the following video: Best practicesWe recommend always using the TIMESTAMPTZ variant because the TIMESTAMP variant can sometimes lead to unexpected behaviors when it ignores a session offset. However, we also recommend you avoid setting a session time zone offset for your database.AliasesIn CockroachDB, the following are aliases:TIMESTAMP, TIMESTAMP WITHOUT TIME ZONETIMESTAMPTZ, TIMESTAMP WITH TIME ZONESyntaxYou can express a constant value of type TIMESTAMP/TIMESTAMPTZ using an interpreted literal, or a string literal annotated with type TIMESTAMP/TIMESTAMPTZ or coerced to type TIMESTAMP/TIMESTAMPTZ. When it is unambiguous, a simple unannotated string literal is automatically interpreted as type TIMESTAMP or TIMESTAMPTZ.You can express TIMESTAMP constants using the following string literal formats:FormatExampleDate onlyTIMESTAMP '2016-01-25'Date and TimeTIMESTAMP '2016-01-25 10:10:10.555555'ISO 8601TIMESTAMP '2016-01-25T10:10:10.555555'To express a TIMESTAMPTZ value with time zone offset from UTC, use the following format: TIMESTAMPTZ '2016-01-25 10:10:10.555555-05:00'. The fractional portion is optional and is rounded to microseconds (6 digits after decimal) for compatibility with the PostgreSQL wire protocol.By default, CockroachDB interprets truncated dates (e.g., 12-16-06) as MM-DD-YY. To change the input string format of truncated dates, set the datestyle session variable or the sql.defaults.datestyle cluster setting.SizeA. Download Change Timestamp [EN] Scarica Change Timestamp [IT] Change Timestamp indir [TR] Pobierz Change Timestamp [PL] Tải xuống Change Timestamp [VI] 下载Change Timestamp [ZH] ダウンロードChange Timestamp [JA] Unduh Change Timestamp [ID] Download do Change Timestamp [PT]How To Change File Timestamps To
TIMESTAMP/TIMESTAMPTZ column supports values up to 12 bytes in width, but the total storage size is likely to be larger due to CockroachDB metadata.PrecisionCockroachDB supports precision levels from 0 (seconds) to 6 (microseconds) for TIMESTAMP/TIMESTAMPTZ values. Precision in time values specifies the number of fractional digits retained in the seconds field. For example, specifying a TIMESTAMPTZ value as TIMESTAMPTZ(3) truncates the time component to milliseconds. By default, TIMESTAMP/TIMESTAMPTZ values have a precision of 6 (microseconds).You can use an ALTER COLUMN ... SET DATA TYPE statement to change the precision level of a TIMESTAMP/TIMESTAMPTZ-typed column. If there is already a non-default precision level specified for the column, the precision level can only be changed to an equal or greater precision level. For an example, see Create a table with a TIMESTAMP-typed column, with precision.Supported casting and conversionTIMESTAMP values can be cast to any of the following data types:TypeDetailsDECIMALConverts to number of seconds since the Unix epoch (Jan. 1, 1970).FLOATConverts to number of seconds since the Unix epoch (Jan. 1, 1970).TIMEConverts to the time portion (HH:MM:SS) of the timestamp.INTConverts to number of seconds since the Unix epoch (Jan. 1, 1970).DATEConverts to the date (YYYY-MM-DD) of the timestamp and omits the other information.STRINGConverts to the date and time portion (YYYY-MM-DD HH:MM:SS) of the timestamp and omits the time zone offset.Infinity TIMESTAMP castsCockroachDB does not support an infinity/-infinity representation for TIMESTAMP casts. Instead, infinity::TIMESTAMP evaluates to 294276-12-31 23:59:59.999999+00:00, the maximum TIMESTAMP value supported, and -infinity::TIMESTAMP evaluates to -4714-11-24 00:00:00+00:00, the minimum TIMESTAMP value supported.Note that this behavior differs from PostgreSQL, for which infinity is higher than any allowable TIMESTAMP value (including 294276-12-31 23:59:59.999999+00:00), and -infinity is lower than any allowable TIMESTAMP value (including -4714-11-24 00:00:00+00:00).ExamplesCreate a table with a TIMESTAMPTZ-typed column icon/buttons/copy > CREATE TABLE timestamps (a INT PRIMARY KEY, b TIMESTAMPTZ); icon/buttons/copy > SHOW COLUMNS FROM timestamps; column_name | data_type | is_nullable | column_default | generation_expression | indices | is_hidden+-------------+-------------+-------------+----------------+-----------------------+-----------+-----------+ a | INT8 | false | NULL | | {primary} | false b | TIMESTAMPTZ | true | NULL | | {primary} | false(2 rows) icon/buttons/copy > INSERT INTO timestamps VALUES (1, TIMESTAMPTZComments
Lfete (Peter´s Blog). Спасибо за содействие!Перевод на Немецкий (Инсталлятор) язык выполнил Maaster (Phillipp Arnold) (Maasters Website). Спасибо за содействие! 2009/08/21Версия:1.03Изменения: - The Window is now resizable. - Added "Secs" and "Mins" for offset menu. - Added "Refresh" button in "View & Copy" mode. - Revised some Japanese texts. 2009/08/09Версия:1.02Изменения: - Added new function "Synchronize To: The Newest File" and "Synchronize To: The Oldest File" in mode "Change Multiple File(s) / Folder(s) at Once". - Changed background color. - Fixed a bug in which "Specific" in mode "Change Multiple File(s) / Folder(s) at Once" was writing wrong time when "Synchronize To: Current Time" was checked. - Added Spanish language support.Перевод на Испанский язык выполнил Adrian from Spain. Спасибо за содействие! 2009/07/21Версия:1.01Изменения: - Fixed a bug in which only single file was being processed when you drop even multiple files in "Change Multiple Files / Folders at Once" mode. - Fixed some bugs in its installer. 2009/07/15Версия:1.00Изменения: - Moo0 TimeStamp 1.00 has been released.------------------------------------------ (Pages for Non-Frame Browser) ------------------------------------------[Moo0 - Полезные бесплатные программы для Windows (not MooO)]:Moo0 Список программMoo0 Список Web ApplicationEnglish): TimeStamp (Free) - Modify File Timestamp | free timestamp software, time stamp software, timestamp editor, timestamp software, timestamp program, timestamp modifier, timestamp changer, timestamp download, change file timestamp, change photo timestampعربي): الطابع الزمني (مجاني) - قم بتعديل ملف الطابع الزمني | برنامج الطابع الزمني مجانا, برنامج الطابع الزمني, برنامج الطابع الزمني, برنامج الطابع الزمني, برنامج الطابع الزمني, معدل الطابع الزمني, مغير الطابع الزمني, الطابع الزمني تحميل, تغيير الطابع الزمني الملف, تغيير الطابع الزمني الصورةБеларускі): TimeStamp (Бясплатна) - Зменіце пазнаку часу файла | свабоднае праграмнае забеспячэнне пазнакі часу, час праграмнае забеспячэнне марка, рэдактар часовай пазнакі, пазнакі часу праграмнае забеспячэнне, пазнакі часу праграма, Мадыфікатар часовай пазнакі, пазнакі часу змены, пазнака часу загрузкі, змяненне файла пазнака часу, змяненне фота пазнака часуDansk): TimeStamp (Gratis)
2025-04-11Free cleaner, cleaner free download, moo0 disk cleanerFile Monitor (Free) - Monitor file access easily | file monitor, filemonitor, monitor file access, file access monitor, file activity monitoring, file-monitor, file access monitoring software, windows file monitor, moo0 file monitor, file monitor windows 7File Shredder (Free) - Erase private files permanently | file shredder, file shredder portable, moo0 file shredder, data shredder, file eraser, erase private file, erase private phote, prevent data recovery, protect private data, fileshredderHash Code (Free) - Calculate / Verify Hash Code | hash code reader, hash code calculate, hash code, easy hash download, hash number, software hash, hashcode download, download hash code, code hash, what is a hash codeTimeStamp (Free) - Modify File Timestamp | free timestamp software, time stamp software, timestamp editor, timestamp software, timestamp program, timestamp modifier, timestamp changer, timestamp download, change file timestamp, change photo timestampColor Picker (Free) - Pick Color from Screen | pickcolor, color picker download, html color picker, color picker chrome, pick color, color picker windows, chrome color picker, windows color picker, html colour picker, colorpickerFont Viewer (Free) - Quickly Find Fonts of your Needs | font viewer, fontviewer, font viewer portable, free font viewer, font viewer free, fonts viewer, windows font viewer, moo font, font viewers, font viewer downloadImage Colors (Free) - Convert Images into Various Color Tones | image colors, change color software, adjust color software free, change image colors, photo colouring software, change photo colors, image color changer, different color tones, change color tones, adjust color tonesImage Converter (Free) - Convert Image Files Easily | png to ico, image converter, convert png to ico, jpg to ico, ico converter, picture converter, ico to png, convert to ico, png to ico converter, jpg to gif converter free downloadImage Sharpener (Free) - Easily Sharpen/Blur image files | image sharpener, photo sharpening software free, photo sharpener, photo sharpening software, picture sharpener, image sharpening software, photo sharpening, picture sharpening software, free photo sharpening software, image sharpening software freeImage Resizer (Free) - Convert Image Sizes Easily | imagesizer, sizer images, image sizer, sizer image, picture size converter, image size converter, moo image, image
2025-04-09It is a special version of "Timestamp Camera" for Instagram, It has been optimized for Instagram. You can add date and location text watermark to photo and video and share to Instagram, so your friends will know when and where it exactly happened.Main features● Add current time and location when recording or capturing, you can change time format or select the location around easily. Timestamp Camera is maybe the only App that can record video with the time accurate to second.- Support 20 timestamp format- Support change font, font color, font size- Support set timestamp in 6 positions: top left, top center, top right, bottom left, bottom center, bottom right- Support auto add location.- Support change timestamp opacity● Support display custom text and emoji on camera. For example, you can input "Good day at the zoo"● Support portrait and landscape● Support change resolutionPlease mail us [email protected] if you have any problem or suggestions. Thank you.
2025-04-13NOTE: This vulnerability no longer affects Ethereum mainnet as of the Proof of Stake merge. Read moreThe timestamp of a block, accessed by block.timestamp or alias now can be manipulated by a miner. There are three considerations you should take into account when using a timestamp to execute a contract function.Timestamp ManipulationIf a timestamp is used in an attempt to generate randomness, a miner can post a timestamp within 15 seconds of block validation, giving them the ability to set the timestamp as a value that would increase their odds of benefitting from the function.For example, a lottery application may use the block timestamp to pick a random bidder in a group. A miner may enter the lottery then modify the timestamp to a value that gives them better odds at winning the lottery.Timestamps should thus not be used to create randomness. See Weak Sources of Randomness for Chain Attributes.The 15-second RuleEthereum's reference specification, the Yellow Paper, doesn't specify a limit as to how much blocks can change in time, it just has to be bigger than the timestamp of its parent. This being said, popular protocol implementations reject blocks with timestamps greater than 15 seconds in the future, so as long as your time-dependent event can safely vary by 15 seconds, it may be safe to use a block timestamp.Don't use block.number as a timestampYou can estimate the time difference between events using block.number and the average block time, but block times may change and break the functionality, so it's best to avoid this use.SourcesConsensys Smart Contract Best Practices - Timestamp Dependence (Attacks)Consensys Smart Contract Best Practices - Timestamp Dependence (Development Recommendations)
2025-04-15'2016-03-26 10:10:10-05:00'), (2, TIMESTAMPTZ '2016-03-26'); icon/buttons/copy > SELECT * FROM timestamps; a | b+---+---------------------------+ 1 | 2016-03-26 15:10:10+00:00 2 | 2016-03-26 00:00:00+00:00(2 rows)Create a table with a TIMESTAMP-typed column, with precision icon/buttons/copy > CREATE TABLE timestamps (a INT PRIMARY KEY, b TIMESTAMP(3)); icon/buttons/copy > SHOW COLUMNS FROM timestamps; column_name | data_type | is_nullable | column_default | generation_expression | indices | is_hidden--------------+--------------+-------------+----------------+-----------------------+-----------+------------ a | INT8 | false | NULL | | {primary} | false b | TIMESTAMP(3) | true | NULL | | {primary} | false(2 rows) icon/buttons/copy > INSERT INTO timestamps VALUES (1, TIMESTAMP '2020-03-25 12:00:00.123456'), (2, TIMESTAMP '2020-03-26 4:00:00.123456'); icon/buttons/copy > SELECT * FROM timestamps; a | b----+-------------------------------- 1 | 2020-03-25 12:00:00.123+00:00 2 | 2020-03-26 04:00:00.123+00:00(2 rows)To change the precision level of a column, you can use an ALTER COLUMN ... SET DATA TYPE statement: icon/buttons/copy > ALTER TABLE timestamps ALTER COLUMN b SET DATA TYPE TIMESTAMP(4); icon/buttons/copy > SHOW COLUMNS FROM timestamps; column_name | data_type | is_nullable | column_default | generation_expression | indices | is_hidden--------------+--------------+-------------+----------------+-----------------------+-----------+------------ a | INT8 | false | NULL | | {primary} | false b | TIMESTAMP(4) | true | NULL | | {primary} | false(2 rows)When changing precision level, TIMESTAMP can be changed to TIMESTAMPTZ, and TIMESTAMPTZ can be changed to TIMESTAMP: icon/buttons/copy > ALTER TABLE timestamps ALTER COLUMN b SET DATA TYPE TIMESTAMPTZ(5); icon/buttons/copy > SHOW COLUMNS FROM timestamps; column_name | data_type | is_nullable | column_default | generation_expression | indices | is_hidden--------------+----------------+-------------+----------------+-----------------------+-----------+------------ a | INT8 | false | NULL | | {primary} | false b | TIMESTAMPTZ(5) | true | NULL | | {primary} | false(2 rows)Note:If a non-default precision level has already been specified, you cannot change the precision to a lower level.In this case, the b column, which is of type TIMESTAMPTZ(5), cannot be changed to a precision level below 5: icon/buttons/copy > ALTER TABLE timestamps ALTER COLUMN b SET DATA TYPE TIMESTAMPTZ(3);ERROR: unimplemented: type conversion from TIMESTAMPTZ(5) to TIMESTAMPTZ(3) requires overwriting existing values which is not yet implementedSQLSTATE: 0A000Convert a TIMESTAMP to seconds since epoch icon/buttons/copy Convert a TIMESTAMP to milliseconds since epoch icon/buttons/copy SELECT (now()::float*1000)::int;Convert a TIMESTAMP to microseconds
2025-03-26This datatype is also known as "rowversion", and the original name is really unfortunate. A timestamp column is automatically updated whenever a row is updated, and the value is monotonically increasing in the database. There is absolutely no relation to date and time. The main purpose of timestamp is to implement optimistic concurrency. The client reads a row from the database gets the timestamp value from the database and sends it back on UPDATE. The UPDATE operation includes a condition on timestamp in the WHERE clause, and if the timestamp value has changed since the client read the value, the update is not performed - and the update that came in-between is not lost. timestamp/rowversion does not seem to be that popular these days, but I have worked with a system where have many of these columns for exactly this reason. Because it is monotonically increasing, some people also use it to find the most recently changed rows in a table, but this is not what it is designed for, and it does not work well in high-concurrency environment. SQL Server offers better features for this purpose, for instance Change Tracking.
2025-04-16