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  • How to install mysql connector

    - by Naresh
    I have downloaded mysqlDb, and while installing it I am getting errors like: C:\Documents and Settings\naresh\Desktop\MySQL-python-1.2.3c1setup.py build Traceback (most recent call last): File "C:\Documents and Settings\naresh\Desktop\MySQL-python-1.2.3c1 \setup.py",line15, in metadata, options = get_config() File "C:\Documents and Settings\naresh\Desktop\MySQL-python-1.2.3c1 \setup_windows.py", line 7, in get_config serverKey = _winreg.OpenKey(_winreg.HKEY_LOCAL_MACHINE, options['registry_key']) WindowsError: [Error 2] The system cannot find the file specified What can I do to address this?

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  • DATE lookup table (1990/01/01:2041/12/31)

    - by Frank Developer
    I use a DATE's master table for looking up dates and other values in order to control several events, intervals and calculations within my app. It has rows for every single day begining from 01/01/1990 to 12/31/2041. One example of how I use this lookup table is: A customer pawned an item on: JAN-31-2010 Customer returns on MAY-03-2010 to make an interest pymt to avoid forfeiting the item. If he pays 1 months interest, the employee enters a "1" and the app looks-up the pawn date (JAN-31-2010) in date master table and puts FEB-28-2010 in the applicable interest pymt date. FEB-28 is returned because FEB-31's dont exist! If 2010 were a leap-year, it would've returned FEB-29. If customer pays 2 months, MAR-31-2010 is returned. 3 months, APR-30... If customer pays more than 3 months or another period not covered by the date lookup table, employee manually enters the applicable date. Here's what the date lookup table looks like: { Copyright 1990:2010, Frank Computer, Inc. } { DBDATE=YMD4- (correctly sorted for faster lookup) } CREATE TABLE datemast ( dm_lookup DATE, {lookup col used for obtaining values below} dm_workday CHAR(2), {NULL=Normal Working Date,} {NW=National Holiday(Working Date),} {NN=National Holiday(Non-Working Date),} {NH=National Holiday(Half-Day Working Date),} {CN=Company Proclamated(Non-Working Date),} {CH=Company Proclamated(Half-Day Working Date)} {several other columns omitted} dm_description CHAR(30), {NULL, holiday description or any comments} dm_day_num SMALLINT, {number of elapsed days since begining of year} dm_days_left SMALLINT, (number of remaining days until end of year} dm_plus1_mth DATE, {plus 1 month from lookup date} dm_plus2_mth DATE, {plus 2 months from lookup date} dm_plus3_mth DATE, {plus 3 months from lookup date} dm_fy_begins DATE, {fiscal year begins on for lookup date} dm_fy_ends DATE, {fiscal year ends on for lookup date} dm_qtr_begins DATE, {quarter begins on for lookup date} dm_qtr_ends DATE, {quarter ends on for lookup date} dm_mth_begins DATE, {month begins on for lookup date} dm_mth_ends DATE, {month ends on for lookup date} dm_wk_begins DATE, {week begins on for lookup date} dm_wk_ends DATE, {week ends on for lookup date} {several other columns omitted} ) IN "S:\PAWNSHOP.DBS\DATEMAST"; Is there a better way of doing this or is it a cool method?

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  • Two strange efficiency problems in Mathematica

    - by Jess Riedel
    FIRST PROBLEM I have timed how long it takes to compute the following statements (where V[x] is a time-intensive function call): Alice = Table[V[i],{i,1,300},{1000}]; Bob = Table[Table[V[i],{i,1,300}],{1000}]^tr; Chris_pre = Table[V[i],{i,1,300}]; Chris = Table[Chris_pre,{1000}]^tr; Alice, Bob, and Chris are identical matricies computed 3 slightly different ways. I find that Chris is computed 1000 times faster than Alice and Bob. It is not surprising that Alice is computed 1000 times slower because, naively, the function V must be called 1000 more times than when Chris is computed. But it is very surprising that Bob is so slow, since he is computed identically to Chris except that Chris stores the intermediate step Chris_pre. Why does Bob evaluate so slowly? SECOND PROBLEM Suppose I want to compile a function in Mathematica of the form f(x)=x+y where "y" is a constant fixed at compile time (but which I prefer not to directly replace in the code with its numerical because I want to be able to easily change it). If y's actual value is y=7.3, and I define f1=Compile[{x},x+y] f2=Compile[{x},x+7.3] then f1 runs 50% slower than f2. How do I make Mathematica replace "y" with "7.3" when f1 is compiled, so that f1 runs as fast as f2? Many thanks!

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  • Executing procedural queries in perl

    - by KalpaG
    I have a query like this set @valid_total:=0; set @invalid_total:=0; select week as weekno, measured_week,project_id as project, role_category_id as role_category, valid_count,valid_tickets, (@valid_total := @valid_total + valid_count) as valid_total, invalid_count,invalid_tickets, (@invalid_total := @invalid_total + invalid_count) as invalid_total from metric_fault_bug_project where measured_week = yearweek(curdate()) and role_category_id = 1 and project_id = 11; it executes fine in heidi (MySQL client) but when it comes to perl, it gives me this error DBD::mysql::st execute failed: You have an error in your SQL syntax; check the m anual that corresponds to your MySQL server version for the right syntax to use near ':=0; set :=0; select week as weekno, measured_week,project_id as project' at line 1 at D:\Mx\scripts\test.pl line 35. Can't execute SQL statement: You have an error in your SQL syntax; check the man ual that corresponds to your MySQL server version for the right syntax to use ne ar ':=0; set :=0; select week as weekno, measured_week,project_id as project' at line 1 The problem seem to be in the set @valid_total := 0; line. I am fairly new to Perl. Can anyone help? this is the complete perl code #!/usr/bin/perl #use lib '/x01/home/kalpag/libs'; use DBI; use strict; use warnings; my $sid = 'issues'; my $user = 'root'; my $passwd = 'kalpa'; my $connection = "DBI:mysql:database=$sid;host=localhost"; my $dbhh = DBI->connect( $connection, $user, $passwd) || die "Database connection not made: $DBI::errstr"; my $sql_query = 'set @valid_total:=0; set @invalid_total:=0; select week as weekno, measured_week,project_id, role_category_id as role_category, valid_count,valid_tickets, (@valid_total := @valid_total + valid_count) as valid_total, invalid_count,invalid_tickets, (@invalid_total := @invalid_total + invalid_count) as invalid_total from metric_fault_bug_project where measured_week = yearweek(curdate()) and role_category_id = 1 and project_id = 11'; my $sth = $dbhh->prepare($sql_query) or die "Can't prepare SQL statement: $DBI::errstr\n"; $sth->execute() or die "Can't execute SQL statement: $DBI::errstr\n"; while ( my @memory = $sth->fetchrow() ) { print "@memory \n"; }

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  • database splitting; multiple tables

    - by Ben
    I am coding a classifieds ad web app. What is the optimal way to structure the database for this? Because of the high repeatability, would it be faster (in terms of searching/indexing) to have a separate table in the database for each city? Or would it be okay to just have one table for every city (it would have a lot of rows..). The classifieds table has id, user_id, city_name, category,[description and detail fields].

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  • How can a not null constraint be dropped?

    - by Tomislav Nakic-Alfirevic
    Let's say there's a table created as follows: create table testTable ( colA int not null ) How would you drop the not null constraint? I'm looking for something along the lines of ALTER TABLE testTable ALTER COLUMN colA DROP NOT NULL; which is what it would look like if I used PostgreSQL. To my amazement, as far as I've been able to find, the MySQL docs, Google and yes, even Stackoverflow (in spite of dozens or hundreds of NULL-related questions) don't seem to lead towards a single simple SQL statement which will do the job.

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  • SQL Bits X – Temporal Snapshot Fact Table Session Slide & Demos

    - by Davide Mauri
    Already 10 days has passed since SQL Bits X in London. I really enjoyed it! Those kind of events are great not only for the content but also to meet friends that – due to distance – is not possible to meet every day. Friends from PASS, SQL CAT, Microsoft, MVP and so on all in one place, drinking beers, whisky and having fun. A perfect mixture for a great learning and sharing experience! I’ve also enjoyed a lot delivering my session on Temporal Snapshot Fact Tables. Given that the subject is very specific I was not expecting a lot of attendees….but I was totally wrong! It seems that the problem of handling daily snapshot of data is more common than what I expected. I’ve also already had feedback from several attendees that applied the explained technique to their existing solution with success. This is just what a speaker in such conference wish to hear! :) If you want to take a look at the slides and the demos, you can find them on SkyDrive: https://skydrive.live.com/redir.aspx?cid=377ea1391487af21&resid=377EA1391487AF21!1151&parid=root The demo is available both for SQL Sever 2008 and for SQL Server 2012. With this last version, you can also simplify the ETL process using the new LEAD analytic function. (This is not done in the demo, I’ve left this option as a little exercise for you :) )

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  • Query doesn't use a covering-index when applicable

    - by Dor
    I've downloaded the employees database and executed some queries for benchmarking purposes. Then I noticed that one query didn't use a covering index, although there was a corresponding index that I created earlier. Only when I added a FORCE INDEX clause to the query, it used a covering index. I've uploaded two files, one is the executed SQL queries and the other is the results. Can you tell why the query uses a covering-index only when a FORCE INDEX clause is added? The EXPLAIN shows that in both cases, the index dept_no_from_date_idx is being used anyway. To adapt myself to the standards of SO, I'm also writing the content of the two files here: The SQL queries: USE employees; /* Creating an index for an index-covered query */ CREATE INDEX dept_no_from_date_idx ON dept_emp (dept_no, from_date); /* Show `dept_emp` table structure, indexes and generic data */ SHOW TABLE STATUS LIKE "dept_emp"; DESCRIBE dept_emp; SHOW KEYS IN dept_emp; /* The EXPLAIN shows that the subquery doesn't use a covering-index */ EXPLAIN SELECT SQL_NO_CACHE * FROM dept_emp INNER JOIN ( /* The subquery should use a covering index, but isn't */ SELECT SQL_NO_CACHE emp_no, dept_no FROM dept_emp WHERE dept_no="d001" ORDER BY from_date DESC LIMIT 20000,50 ) AS `der` USING (`emp_no`, `dept_no`); /* The EXPLAIN shows that the subquery DOES use a covering-index, thanks to the FORCE INDEX clause */ EXPLAIN SELECT SQL_NO_CACHE * FROM dept_emp INNER JOIN ( /* The subquery use a covering index */ SELECT SQL_NO_CACHE emp_no, dept_no FROM dept_emp FORCE INDEX(dept_no_from_date_idx) WHERE dept_no="d001" ORDER BY from_date DESC LIMIT 20000,50 ) AS `der` USING (`emp_no`, `dept_no`); The results: -------------- /* Creating an index for an index-covered query */ CREATE INDEX dept_no_from_date_idx ON dept_emp (dept_no, from_date) -------------- Query OK, 331603 rows affected (33.95 sec) Records: 331603 Duplicates: 0 Warnings: 0 -------------- /* Show `dept_emp` table structure, indexes and generic data */ SHOW TABLE STATUS LIKE "dept_emp" -------------- +----------+--------+---------+------------+--------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-----------------+----------+----------------+---------+ | Name | Engine | Version | Row_format | Rows | Avg_row_length | Data_length | Max_data_length | Index_length | Data_free | Auto_increment | Create_time | Update_time | Check_time | Collation | Checksum | Create_options | Comment | +----------+--------+---------+------------+--------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-----------------+----------+----------------+---------+ | dept_emp | InnoDB | 10 | Compact | 331883 | 36 | 12075008 | 0 | 21544960 | 29360128 | NULL | 2010-05-04 13:07:49 | NULL | NULL | utf8_general_ci | NULL | | | +----------+--------+---------+------------+--------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-----------------+----------+----------------+---------+ 1 row in set (0.47 sec) -------------- DESCRIBE dept_emp -------------- +-----------+---------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-----------+---------+------+-----+---------+-------+ | emp_no | int(11) | NO | PRI | NULL | | | dept_no | char(4) | NO | PRI | NULL | | | from_date | date | NO | | NULL | | | to_date | date | NO | | NULL | | +-----------+---------+------+-----+---------+-------+ 4 rows in set (0.05 sec) -------------- SHOW KEYS IN dept_emp -------------- +----------+------------+-----------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | +----------+------------+-----------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+ | dept_emp | 0 | PRIMARY | 1 | emp_no | A | 331883 | NULL | NULL | | BTREE | | | dept_emp | 0 | PRIMARY | 2 | dept_no | A | 331883 | NULL | NULL | | BTREE | | | dept_emp | 1 | emp_no | 1 | emp_no | A | 331883 | NULL | NULL | | BTREE | | | dept_emp | 1 | dept_no | 1 | dept_no | A | 7 | NULL | NULL | | BTREE | | | dept_emp | 1 | dept_no_from_date_idx | 1 | dept_no | A | 13 | NULL | NULL | | BTREE | | | dept_emp | 1 | dept_no_from_date_idx | 2 | from_date | A | 165941 | NULL | NULL | | BTREE | | +----------+------------+-----------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+ 6 rows in set (0.23 sec) -------------- /* The EXPLAIN shows that the subquery doesn't use a covering-index */ EXPLAIN SELECT SQL_NO_CACHE * FROM dept_emp INNER JOIN ( /* The subquery should use a covering index, but isn't */ SELECT SQL_NO_CACHE emp_no, dept_no FROM dept_emp WHERE dept_no="d001" ORDER BY from_date DESC LIMIT 20000,50 ) AS `der` USING (`emp_no`, `dept_no`) -------------- +----+-------------+------------+--------+----------------------------------------------+-----------------------+---------+------------------------+-------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+------------+--------+----------------------------------------------+-----------------------+---------+------------------------+-------+-------------+ | 1 | PRIMARY | <derived2> | ALL | NULL | NULL | NULL | NULL | 50 | | | 1 | PRIMARY | dept_emp | eq_ref | PRIMARY,emp_no,dept_no,dept_no_from_date_idx | PRIMARY | 16 | der.emp_no,der.dept_no | 1 | | | 2 | DERIVED | dept_emp | ref | dept_no,dept_no_from_date_idx | dept_no_from_date_idx | 12 | | 21402 | Using where | +----+-------------+------------+--------+----------------------------------------------+-----------------------+---------+------------------------+-------+-------------+ 3 rows in set (0.09 sec) -------------- /* The EXPLAIN shows that the subquery DOES use a covering-index, thanks to the FORCE INDEX clause */ EXPLAIN SELECT SQL_NO_CACHE * FROM dept_emp INNER JOIN ( /* The subquery use a covering index */ SELECT SQL_NO_CACHE emp_no, dept_no FROM dept_emp FORCE INDEX(dept_no_from_date_idx) WHERE dept_no="d001" ORDER BY from_date DESC LIMIT 20000,50 ) AS `der` USING (`emp_no`, `dept_no`) -------------- +----+-------------+------------+--------+----------------------------------------------+-----------------------+---------+------------------------+-------+--------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+------------+--------+----------------------------------------------+-----------------------+---------+------------------------+-------+--------------------------+ | 1 | PRIMARY | <derived2> | ALL | NULL | NULL | NULL | NULL | 50 | | | 1 | PRIMARY | dept_emp | eq_ref | PRIMARY,emp_no,dept_no,dept_no_from_date_idx | PRIMARY | 16 | der.emp_no,der.dept_no | 1 | | | 2 | DERIVED | dept_emp | ref | dept_no_from_date_idx | dept_no_from_date_idx | 12 | | 37468 | Using where; Using index | +----+-------------+------------+--------+----------------------------------------------+-----------------------+---------+------------------------+-------+--------------------------+ 3 rows in set (0.05 sec) Bye

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  • How do I align my partition table properly?

    - by Jorge Castro
    I am in the process of building my first RAID5 array. I've used mdadm to create the following set up: root@bondigas:~# mdadm --detail /dev/md1 /dev/md1: Version : 00.90 Creation Time : Wed Oct 20 20:00:41 2010 Raid Level : raid5 Array Size : 5860543488 (5589.05 GiB 6001.20 GB) Used Dev Size : 1953514496 (1863.02 GiB 2000.40 GB) Raid Devices : 4 Total Devices : 4 Preferred Minor : 1 Persistence : Superblock is persistent Update Time : Wed Oct 20 20:13:48 2010 State : clean, degraded, recovering Active Devices : 3 Working Devices : 4 Failed Devices : 0 Spare Devices : 1 Layout : left-symmetric Chunk Size : 64K Rebuild Status : 1% complete UUID : f6dc829e:aa29b476:edd1ef19:85032322 (local to host bondigas) Events : 0.12 Number Major Minor RaidDevice State 0 8 16 0 active sync /dev/sdb 1 8 32 1 active sync /dev/sdc 2 8 48 2 active sync /dev/sdd 4 8 64 3 spare rebuilding /dev/sde While that's going I decided to format the beast with the following command: root@bondigas:~# mkfs.ext4 /dev/md1p1 mke2fs 1.41.11 (14-Mar-2010) /dev/md1p1 alignment is offset by 63488 bytes. This may result in very poor performance, (re)-partitioning suggested. Filesystem label= OS type: Linux Block size=4096 (log=2) Fragment size=4096 (log=2) Stride=16 blocks, Stripe width=48 blocks 97853440 inodes, 391394047 blocks 19569702 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=0 11945 block groups 32768 blocks per group, 32768 fragments per group 8192 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968, 102400000, 214990848 Writing inode tables: ^C 27/11945 root@bondigas:~# ^C I am unsure what to do about "/dev/md1p1 alignment is offset by 63488 bytes." and how to properly partition the disks to match so I can format it properly.

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  • Evaluation of CTEs in SQL Server 2005

    - by Jammer
    I have a question about how MS SQL evaluates functions inside CTEs. A couple of searches didn't turn up any results related to this issue, but I apologize if this is common knowledge and I'm just behind the curve. It wouldn't be the first time :-) This query is a simplified (and obviously less dynamic) version of what I'm actually doing, but it does exhibit the problem I'm experiencing. It looks like this: CREATE TABLE #EmployeePool(EmployeeID int, EmployeeRank int); INSERT INTO #EmployeePool(EmployeeID, EmployeeRank) SELECT 42, 1 UNION ALL SELECT 43, 2; DECLARE @NumEmployees int; SELECT @NumEmployees = COUNT(*) FROM #EmployeePool; WITH RandomizedCustomers AS ( SELECT CAST(c.Criteria AS int) AS CustomerID, dbo.fnUtil_Random(@NumEmployees) AS RandomRank FROM dbo.fnUtil_ParseCriteria(@CustomerIDs, 'int') c) SELECT rc.CustomerID, ep.EmployeeID FROM RandomizedCustomers rc JOIN #EmployeePool ep ON ep.EmployeeRank = rc.RandomRank; DROP TABLE #EmployeePool; The following can be assumed about all executions of the above: The result of dbo.fnUtil_Random() is always an int value greater than zero and less than or equal to the argument passed in. Since it's being called above with @NumEmployees which has the value 2, this function always evaluates to 1 or 2. The result of dbo.fnUtil_ParseCriteria(@CustomerIDs, 'int') produces a one-column, one-row table that contains a sql_variant with a base type of 'int' that has the value 219935. Given the above assumptions, it makes sense (to me, anyway) that the result of the expression above should always produce a two-column table containing one record - CustomerID and an EmployeeID. The CustomerID should always be the int value 219935, and the EmployeeID should be either 42 or 43. However, this is not always the case. Sometimes I get the expected single record. Other times I get two records (one for each EmployeeID), and still others I get no records. However, if I replace the RandomizedCustomers CTE with a true temp table, the problem vanishes completely. Every time I think I have an explanation for this behavior, it turns out to not make sense or be impossible, so I literally cannot explain why this would happen. Since the problem does not happen when I replace the CTE with a temp table, I can only assume it has something to do with the functions inside CTEs are evaluated during joins to that CTE. Do any of you have any theories?

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  • ActiveRecord table inheritence using set_table_names

    - by Jinyoung Kim
    Hi, I'm using ActiveRecord in Ruby on Rails. I have a table named documents(Document class) and I want to have another table data_documents(DataDocument) class which is effectively the same except for having different table name. In other words, I want two tables with the same behavior except for table name. class DataDocument < Document #set_table_name "data_documents" self.table_name = "data_documents" end My solution was to use class inheritance as above, yet this resulted in inconsistent SQL statement for create operation where there are both 'documents' table and 'data_documents' table. Can you figure out why and how I can make it work? >> DataDocument.create(:did=>"dd") ActiveRecord::StatementInvalid: Mysql::Error: Unknown column 'data_documents.did' in 'where clause': SELECT `documents`.id FROM `documents` WHERE (`data_documents`.`did` = BINARY 'dd') LIMIT 1 from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract_adapter.rb:212:in `log' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/mysql_adapter.rb:320:in `execute' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/mysql_adapter.rb:595:in `select' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/database_statements.rb:7:in `select_all_without_query_cache' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:62:in `select_all'

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  • Using a PivotTable to Count Items in Access

    - by Sandra
    I have a list of text entries and I want to count how often each entry appears in the list. e.g. Berlin Paris London London Paris Paris Paris The result would be Berlin 1 Paris 4 London 2 This result easy do to achieve with an pivot table in MS Excel (see: Count Items in Excel). My data not in spreadsheet in Excel but in a MS Access database table. So in order to avoid constant switching between Access and Excel and I would like to handle everything in Access (either Access 2007 or 2010). I know there are pivot tables in Access and I know how to display one, but I was unable to find out how to count the number of occurrences. Thank you!

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  • Five Query Optimizations in MySQL

    Query optimization is an often overlooked part of applications. Sean Hull encourages at least some attention to query optimization up front and helps you identify some of the more common optimizations you may run across.

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  • How do I delete a foreign key in SQLAlchemy?

    - by Travis
    I'm using SQLAlchemy Migrate to keep track of database changes and I'm running into an issue with removing a foreign key. I have two tables, t_new is a new table, and t_exists is an existing table. I need to add t_new, then add a foreign key to t_exists. Then I need to be able to reverse the operation (which is where I'm having trouble). t_new = sa.Table("new", meta.metadata, sa.Column("new_id", sa.types.Integer, primary_key=True) ) t_exists = sa.Table("exists", meta.metadata, sa.Column("exists_id", sa.types.Integer, primary_key=True), sa.Column( "new_id", sa.types.Integer, sa.ForeignKey("new.new_id", onupdate="CASCADE", ondelete="CASCADE"), nullable=False ) ) This works fine: t_new.create() t_exists.c.new_id.create() But this does not: t_exists.c.new_id.drop() t_new.drop() Trying to drop the foreign key column gives an error: 1025, "Error on rename of '.\my_db_name\#sql-1b0_2e6' to '.\my_db_name\exists' (errno: 150)" If I do this with raw SQL, i can remove the foreign key manually then remove the column, but I haven't been able to figure out how to remove the foreign key with SQLAlchemy? How can I remove the foreign key, and then the column?

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  • Temp Table Recompiles

    - by Derek D.
    If you landed on this article, then you most likely know that temp tables can cause recompilation. This happens because temp tables are treated just like regular tables by the SQL Server Engine. When the tables (in which underlying queries rely on) change significantly, SQL Server detects this change (using auto update statistics) [...]

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  • How to get hibernate3-maven-plugin hbm2ddl to find JDBC driver?

    - by HDave
    I have a Java project I am building with Maven. I am now trying to get the hibernate3-maven-plugin to run the hbm2ddl tool to generate a schema.sql file I can use to create the database schema from my annotated domain classes. This is a JPA application that uses Hibernate as the provider. In my persistence.xml file I call out the mysql driver: <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/> <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver"/> When I run Maven, I see it processing all my classes, but when it goes to output the schema, I get the following error: ERROR org.hibernate.connection.DriverManagerConnectionProvider - JDBC Driver class not found: com.mysql.jdbc.Driver java.lang.ClassNotFoundException: com.mysql.jdbc.Driver I have the MySQL driver as a dependency of this module. However it seems like the hbm2ddl tool cannot find it. I would have guessed that the Maven plugin would have known to search the local Maven file repository for this driver. What gives? The relevant part of my pom.xml is this: <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>hibernate3-maven-plugin</artifactId> <executions> <execution> <phase>process-classes</phase> <goals> <goal>hbm2ddl</goal> </goals> </execution> </executions> <configuration> <components> <component> <name>hbm2ddl</name> <implementation>jpaconfiguration</implementation> </component> </components> <componentProperties> <persistenceunit>my-unit</persistenceunit> </componentProperties> </configuration> </plugin>

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  • Does query plan optimizer works well with joined/filtered table-valued functions?

    - by smoothdeveloper
    In SQLSERVER 2005, I'm using table-valued function as a convenient way to perform arbitrary aggregation on subset data from large table (passing date range or such parameters). I'm using theses inside larger queries as joined computations and I'm wondering if the query plan optimizer work well with them in every condition or if I'm better to unnest such computation in my larger queries. Does query plan optimizer unnest table-valued functions if it make sense? If it doesn't, what do you recommend to avoid code duplication that would occur by manually unnesting them? If it does, how do you identify that from the execution plan? code sample: create table dbo.customers ( [key] uniqueidentifier , constraint pk_dbo_customers primary key ([key]) ) go /* assume large amount of data */ create table dbo.point_of_sales ( [key] uniqueidentifier , customer_key uniqueidentifier , constraint pk_dbo_point_of_sales primary key ([key]) ) go create table dbo.product_ranges ( [key] uniqueidentifier , constraint pk_dbo_product_ranges primary key ([key]) ) go create table dbo.products ( [key] uniqueidentifier , product_range_key uniqueidentifier , release_date datetime , constraint pk_dbo_products primary key ([key]) , constraint fk_dbo_products_product_range_key foreign key (product_range_key) references dbo.product_ranges ([key]) ) go . /* assume large amount of data */ create table dbo.sales_history ( [key] uniqueidentifier , product_key uniqueidentifier , point_of_sale_key uniqueidentifier , accounting_date datetime , amount money , quantity int , constraint pk_dbo_sales_history primary key ([key]) , constraint fk_dbo_sales_history_product_key foreign key (product_key) references dbo.products ([key]) , constraint fk_dbo_sales_history_point_of_sale_key foreign key (point_of_sale_key) references dbo.point_of_sales ([key]) ) go create function dbo.f_sales_history_..snip.._date_range ( @accountingdatelowerbound datetime, @accountingdateupperbound datetime ) returns table as return ( select pos.customer_key , sh.product_key , sum(sh.amount) amount , sum(sh.quantity) quantity from dbo.point_of_sales pos inner join dbo.sales_history sh on sh.point_of_sale_key = pos.[key] where sh.accounting_date between @accountingdatelowerbound and @accountingdateupperbound group by pos.customer_key , sh.product_key ) go -- TODO: insert some data -- this is a table containing a selection of product ranges declare @selectedproductranges table([key] uniqueidentifier) -- this is a table containing a selection of customers declare @selectedcustomers table([key] uniqueidentifier) declare @low datetime , @up datetime -- TODO: set top query parameters . select saleshistory.customer_key , saleshistory.product_key , saleshistory.amount , saleshistory.quantity from dbo.products p inner join @selectedproductranges productrangeselection on p.product_range_key = productrangeselection.[key] inner join @selectedcustomers customerselection on 1 = 1 inner join dbo.f_sales_history_..snip.._date_range(@low, @up) saleshistory on saleshistory.product_key = p.[key] and saleshistory.customer_key = customerselection.[key] I hope the sample makes sense. Much thanks for your help!

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  • SQL SERVER Size of Index Table for Each Index Solution 3 Powershell

    Laerte Junior If you are a Powershell user, the name of the Laerte Junior is not a new name. He is the one man with exceptional knowledge of Powershell. He is not only very knowledgeable, but also very kind and eager to those in need. I have been attempting to setup Powershell for many days, [...]...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • SQL SERVER Size of Index Table for Each Index Solution 3 Powershell

    Laerte Junior If you are a Powershell user, the name of the Laerte Junior is not a new name. He is the one man with exceptional knowledge of Powershell. He is not only very knowledgeable, but also very kind and eager to those in need. I have been attempting to setup Powershell for many days, [...]...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • how to 'scale' these three tables?

    - by iddqd
    I have the following Tables: Players id playerName Weapons id type otherData Weapons2Player id playersID_reference weaponsID_reference That was nice and simple. Now I need to SELECT items from the Weapons table, according to some of their characteristics that i previously just packed into the otherData column (since it was only needed on the client side). The problem is, that the types have varying characteristics - but also a lot of similar data. So I'm trying to decide on the following possibilities, all of which have their pros and cons. Solution A Kill the Weapons table, and create a new table for each Weapon-Type: Weapons_Swords id bladeType damage otherData Weapons_Guns id accuracy damage ammoType otherData But how will i Link these to the Players ? create Weapons_Swords2Players, Weapons_Guns2Players for each weapon-type? (Will result in a lot more JOINS when loading the player with all his weapons...and it's also more complicated to insert a new player) or add another column to Weapons2Players called WeaponsTypeTable, then do sub-selects to the correct Weapons sub-table (seems easier, but not really right, slightly easier insert i guess) Solution B Keep the Weapons table, and add all the fields i need to it. The Problem is that then there will be NULL fields, since not all Weapon-Types use all fields (can't be right) Weapons id type accuracy damage ammoType bladeType otherData This seems to be pretty basic stuff, but i just can't decide what's best. Or is there a correct Solution C? many thanks.

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