sql-update

问题 I need to create script in linux. There is command like: psql -U postgres -d ticketon -c "UPDATE "user" SET "password" = 'test'" When I put it to quotation marks, there is mistake. When out of quotation marks, there also is error. I have tried almost everything, but still without success. Do anyone know what is correct syntax? 回答1: How a_horse_with_no_name said. psql -U postgres -d dbName -c "UPDATE \"user\" SET \"password\" = 'test'" 回答2: I was doing something similar recently. What you want

问题 I will have multiple clients entering data into a database and I must ensure that the transactions do not get intermingled. I read in the documentation that START TRANSACTION and SELECT ... FOR UPDATE locks each row that it reads: A SELECT ... FOR UPDATE reads the latest available data, setting exclusive locks on each row it reads. Thus, it sets the same locks a searched SQL UPDATE would set on the rows. See https://dev.mysql.com/doc/refman/5.0/en/innodb-locking-reads.html So I logged in one

问题 declare @id int declare @empid int set @id = 0 declare @schedindate datetime declare @ss nvarchar(100) declare @indice nvarchar(2) declare @FromDate datetime declare @ToDate datetime declare @TimeInR datetime declare @TimeOutR datetime set @FromDate = '2009-01-14' set @ToDate = '2010-01-30' Declare cc cursor for select distinct empid from ta_timecard where schedindate between @FromDate and @ToDate open cc fetch next from cc into @empid while (@@fetch_status = 0) begin set @id = @id + 1 insert

问题 As I understand, when "Update" is called, every property within a specific entity is modified. The "Attach" method, on the other hand, starts the entity off in the "Unmodified" state. Then, when an operation takes place on a particular property, that specific property only is modified. So "Attach" is more useful for individual property changes, and "Update" is more useful when you want to update every property in the entity (I may be wrong in this understanding). However, what I don't

问题 As I understand, when "Update" is called, every property within a specific entity is modified. The "Attach" method, on the other hand, starts the entity off in the "Unmodified" state. Then, when an operation takes place on a particular property, that specific property only is modified. So "Attach" is more useful for individual property changes, and "Update" is more useful when you want to update every property in the entity (I may be wrong in this understanding). However, what I don't

问题 I've working on this problem for a while, and I've been stuck for a few days. What I have is a basic blog system, and right now I'm stuck on trying to delete/hide posts from a list. if(isset($_POST['hideBtn']) && isset($_POST['hidePost'])){ $checked = $_POST['hidePost']; print_r($checked); } elseif(isset($_POST['hideBtn']) && !isset($_POST['hidePost'])){ echo "Nothing Selected"; } There is a checkbox for each post that shows up in the list. <input type="checkbox" name="hidePost[]" value="<

问题 I've working on this problem for a while, and I've been stuck for a few days. What I have is a basic blog system, and right now I'm stuck on trying to delete/hide posts from a list. if(isset($_POST['hideBtn']) && isset($_POST['hidePost'])){ $checked = $_POST['hidePost']; print_r($checked); } elseif(isset($_POST['hideBtn']) && !isset($_POST['hidePost'])){ echo "Nothing Selected"; } There is a checkbox for each post that shows up in the list. <input type="checkbox" name="hidePost[]" value="<

问题 Suppose I have a table named 't' --------------- | key | value | --------------- | 1 | abc | | 2 | def | --------------- Consider two MYSQL queries UPDATE t SET value='abc' WHERE key=1 UPDATE t SET value='abc' WHERE key=3 Executing both queries also give the 'affected rows' is 0 (That is, do NOT update any row) because first query is an non-updating update and second is an non-matching update. Is there any way to distinguish these two cases? 回答1: if you only want the number of 'matched' rows

问题 Suppose I have a table named 't' --------------- | key | value | --------------- | 1 | abc | | 2 | def | --------------- Consider two MYSQL queries UPDATE t SET value='abc' WHERE key=1 UPDATE t SET value='abc' WHERE key=3 Executing both queries also give the 'affected rows' is 0 (That is, do NOT update any row) because first query is an non-updating update and second is an non-matching update. Is there any way to distinguish these two cases? 回答1: if you only want the number of 'matched' rows

问题 I develop an project using JPA along with Hibernate and I have two threads: Thread A: is always reading and outputs the differences Thread B: has some write operations and one transaction which is committed after finishing writing data If I delete data or insert new data from/in the database, after committing transactions from Thread B, in Thread A I see the differences, that some data was removed or added. My problem is when I update existing data: after committing, Thread A doesn't see the