Delete multiple objects from a SQL Server database - sql

Is there a way to delete multiple object inside database? I have 20 tables, 40 views, 40 stored procedures, 20 triggers.
I don't want to delete them one by one. I've been naming all the objects starting with _, e.g. _TableName, _ViewName, _StoredProcedureName, etc.
Thank you.

You can achieve that using dynamic SQL and query catalog views for your objects (there's one for tables, views, procedures, etc.). You can then build up a list of drop statement separated by ; and execute it.
For example, for dropping tables it will be:
declare #sql nvarchar(max) = N''
select #sql = #sql + N'drop table ' + QUOTENAME(s.name) + N'.' + QUOTENAME(t.name) + N'; '
from sys.tables t
inner join sys.schemas s on t.schema_id = s.schema_id
where left(t.name, 1) = '_'
exec sp_executesql #sql

Related

Dynamic SQL w/ Loop Over All Columns in a Table

I recently was pulled off of an ASP.net conversion project at my new job to help with a rather slow, mundane, but desperate task another department is handling. Basically, they are using a simple SQL script on every column of every table in every database (it's horrible) to generate a count of all of the distinct records on each table for each column. My SQL experience is limited and my dynamic SQL experience is zero, more or less, but since I have not been given permissions yet to even access this particular database I went to work attempting to formulate a more automated query to perform this task, testing on a database I do have access to.
In short, I ran into some issues and I was hoping someone might be able to help me fill in the blanks. It'll save this department more than a month of speculated time if something more automated can be utilized.
These are the two scripts I was given and told to run on each column. The first one was for any non-bit/boolean column and also for non-datetime columns. The second was to be used for any datetime column.
select columnName, count(*) qty
from tableName
group by columnName
order by qty desc
select year(a.columnName), count(*) qty
from tableName a
group by year(a.columnName)
order by qty desc
Doing this thousands of times doesn't seem like a lot of fun to me, so here is more or less some pseudo-code that I came up with that I think could solve the issue, I will point out which areas I am fuzzy on.
declare #sql nvarchar(2500)
set #sql = 'the first part(s) of statement'
[pseudo-pseudo] Get "List" of All Column Names in Table (I do not believe there is a Collection datatype in SQL code, but you get the idea)
[pseudo-pseudo] Loop Through "List" of Column Names
(I know this dot notation wouldn't work, but I would like to perform something similar to this)
IF ColumnName.DataType LIKE 'date%'
set #sql = #sql + ' something'
IF ColumnName.DataType = bit
set #sql = #sql + ' something else' --actually it'd be preferable to skip bit/boolean datatypes if possible as these aren't necessary for the reports being created by these queries
ELSE
set #sql = #sql + ' something other than something else'
set #sql = #sql + ' ending part of statement'
EXEC(#sql)
So to summarize, for simplicity's sake I'd like to let the user plug the table's name into a variable at the start of the query:
declare #tableName nvarchar(50)
set #tableName = 'TABLENAME' --Enter Query's Table Name Here
Based on this, the code will loop through every column of that table, checking for datatype. If the datatype is a datetime (or other date like datatype), the "year" code would be added to the dynamic SQL. If it is anything else (except bit/boolean), then it will add the default logic to the dynamic SQL code.
Again, for simplicity's sake (even if it is bad practice) I figure the end result will be a dynamic SQL statement with multiple selects, one for each column in the table. Then the user would simply copy the output to excel (which they are doing right now anyway). I know this isn't the perfect solution so I am open to suggestions, but since time is of the essence and my experience with dynamic SQL is close to null, I thought a somewhat quick and dirty approach would be tolerable in this case.
I do apologize for my very haphazard preparation with this question but I do hope someone out there might be able to steer me in the right direction.
Thanks so much for your time, I certainly appreciate it.
Here's an example working through all the suggestions in the comments.
declare #sql nvarchar(max);
declare stat_cursor cursor local fast_forward for
select
case when x.name not in ('date', 'datetime2', 'smalldatetime', 'datetime') then
N'select
' + quotename(s.name, '''') + ' as schema_name,
' + quotename(t.name, '''') + ' as table_name,
' + quotename(c.name) + ' as column_name,
count(*) qty
from
' + quotename(s.name) + '.' + quotename(t.name) + '
group by
' + quotename(c.name) + '
order by
qty desc;'
else
N'select
' + quotename(s.name, '''') + ' as schema_name,
' + quotename(t.name, '''') + ' as table_name,
year(' + quotename(c.name) + ') as column_name,
count(*) qty
from
' + quotename(s.name) + '.' + quotename(t.name) + '
group by
year(' + quotename(c.name) + ')
order by
qty desc;'
end
from
sys.schemas s
inner join
sys.tables t
on s.schema_id = t.schema_id
inner join
sys.columns c
on c.object_id = t.object_id
inner join
sys.types x
on c.system_type_id = x.user_type_id
where
x.name not in (
'geometry',
'geography',
'hierarchyid',
'xml',
'timestamp',
'bit',
'image',
'text',
'ntext'
);
open stat_cursor;
fetch next from stat_cursor into #sql;
while ##fetch_status = 0
begin
exec sp_executesql #sql;
fetch next from stat_cursor into #sql;
end;
close stat_cursor;
deallocate stat_cursor;
Example SQLFiddle (note this only shows the first iteration through the cursor. Not sure if this is a limitation of SQLFiddle or a bug).
I'd probably stash the results into a separate database if I was doing this. Also, I'd probably put the SQL building bits into user defined functions for maintainability (the slow bit will be running the queries, no point optimizing generating them).

How to create an alias of database in SQL Server

We have a very old software has been created around 10 years ago and we don't have source code.
The software uses two databases, DB01 and DB02 on the same SQL Server 2012 instance.
There is SQL statements such as db01..table1 join db02..table2, but the main issue is our processes don't allow us use db02 as a name of database.
The question is: how we can create an alias of for database?
I was trying to use CREATE SYNONYM
CREATE SYNONYM [db02] FOR [db02_new_name];
but it doesn't work for database names.
Please suggest how it can be solved without patching a binary files to correct SQL statements.
Create a database with the name you want to impersonate. Re-jigg the DDL code generator to create a view for every table in the database that has the tables I need to access via the hardcoded name. Basically, each view will have a statement that looks like this..
CREATE VIEW schemaname.tablename as SELECT * FROM targetdbname.schemaname.tablename
Example:
The target database name that is hardcoded is called ProdDBV1 and the Source DB you have is named ProductDatabaseDatabaseV1, schema is dbo and table name is customer
Create the database called ProdDBV1 using SSMS or script.
CREATE VIEW dbo.customer as SELECT * FROM ProductDatabaseDatabaseV1.dbo.customer
If you can enumerate each table in your "source" database and then create the DDL as above. If you want I can update this posting with a code example. (using the sp_msforeachtable procedure if possible)
I had a similar issue.
Solved with this workaround, using synonyms.
Short version: You flood your database with a synonym of every object you'll ever need to reference. Later you re-create every synonym with the other database name.
Here's a stored proc to do it. Simply add it to your database and call it with the target database. It will create synonyms for all tables in the target database, and create the schemas if they don't exist. I've left a commented out section in case someone knows of a way to get the create schemas working without a cursor.
CREATE PROCEDURE CreateSynonymsForTargetDatabase (
#databaseName sysname
)
AS BEGIN
DECLARE #TSQL nvarchar(max) = N''
DECLARE #rn char(2),
#SchemaName sysname;
SET #rn = char(13) + char(10)
CREATE TABLE #DBSynonym(
[Schema] sysname NOT NULL,
[Table] sysname NOT NULL
)
SET #TSQL = N'
INSERT INTO #DBSynonym ([Schema], [Table])
SELECT Schemas.name, Tables.name
FROM [' + #databaseName + '].sys.tables
INNER JOIN [' + #databaseName + '].sys.schemas on tables.schema_id = schemas.schema_id
'
EXEC (#TSQL)
SET #TSQL = N''
DECLARE MissingSchemasCursor CURSOR
READ_ONLY
FOR
SELECT newSchemas.[Schema]
FROM #DBSynonym newSchemas
LEFT JOIN sys.schemas on newSchemas.[Schema] = schemas.name
WHERE schemas.schema_id is null
GROUP BY newSchemas.[Schema]
OPEN MissingSchemasCursor
FETCH NEXT FROM MissingSchemasCursor INTO #SchemaName
WHILE (##fetch_status <> -1)
BEGIN
IF (##fetch_status <> -2)
BEGIN
SET #TSQL = N'CREATE SCHEMA ' + QUOTENAME(#SchemaName) + N';'
EXEC sp_executesql #TSQL
END
FETCH NEXT FROM MissingSchemasCursor INTO #SchemaName
END
CLOSE MissingSchemasCursor
DEALLOCATE MissingSchemasCursor
/*
SELECT #TSQL = #TSQL +
N'
GO
CREATE SCHEMA ' + QUOTENAME([Schema]) + N';'
FROM #DBSynonym newSchemas
LEFT JOIN sys.schemas on newSchemas.[Schema] = schemas.name
WHERE schemas.schema_id is null
GROUP BY newSchemas.[Schema]
PRINT 'CREATE SCHEMAS : ' + ISNULL(#TSQL,'')
EXEC sp_executesql #TSQL
*/
SET #TSQL = N''
SELECT #TSQL = #TSQL +
N'
CREATE SYNONYM ' + QUOTENAME([Schema]) + N'.' + QUOTENAME([Table]) + N'
FOR ' + QUOTENAME(#databaseName) + N'.' + QUOTENAME([Schema]) + N'.' + QUOTENAME([Table]) + N';'
FROM #DBSynonym
EXEC sp_executesql #TSQL
SET #TSQL = N''
END
GO
Use it as follows :
EXEC CreateSynonymsForTargetDatabase 'targetDbName'
The question is: how we can create an alias of for database?
I know this is an old post but...
This is why I only use the 2 part naming convention for SQL objects. It allows me to have 2 part synonyms that point to differently named databases depending on what environment I'm in. There are some places where it doesn't work so well but, for the most part, those places are very rare.
As for software that you don't have the source code of and if that software uses the 3 part naming convention, you're probably just out of luck unless you know what the 3 part naming convention is for each object and create a 3 part synonym for each object.
I found Charles' answer (and the linked workaround in the comment by maxcastaneda) very useful. I followed this approach and it works for me. I have streamlined it a bit and created the following query that brings up all required synonyms to create.
As a prerequisite for this snippet both the original DB and the synonym/alias db have to be on the same server otherwise in case you use linked server or so you have to modify it a bit.
It should be fairly easy to put this into a small sp to update the synonyms automatically.
USE <SYNONYMDB>
SELECT
'[' + TABLE_NAME + ']',
'[' + TABLE_SCHEMA + '].[' + TABLE_NAME + ']',
'IF EXISTS (SELECT * FROM sys.synonyms WHERE name = ''' + TABLE_NAME + ''') DROP SYNONYM ['+ TABLE_NAME + ']; CREATE SYNONYM [' + TABLE_NAME + '] FOR <ORIGINALDB>.' + TABLE_SCHEMA + '.[' + TABLE_NAME + ']' AS SynonymUpdateScript FROM <ORIGINALDB>.INFORMATION_SCHEMA.TABLES
Don't forget to enter you Db names at the <...> spots.
Just copy the content of the SynonymUpdateScript Column and execute it in the synonym DB - or create a stored procedure for this task.
Be aware there is an issue if you have views in place that refer to tables or other db objects without the 2 part naming convention. Those synonyms won't work. You should fix this in the original objects / views.
Go to the Database you wish to create Alias,
Create an Alias Folders table with the preferred design,
Go to unique IDs's table and check the last code sequence for the table created.
For example, if the last code is 10, then update it to 11.
Open Cabinets table and go right at the bottom and create the name of the Alias cabinet you want.
You can create an alias from 'SQL Server Configuration Manager' under Configuartion Tool in SQL Server Folder.
Detailed source : http://www.mssqltips.com/sqlservertip/1620/how-to-setup-and-use-a-sql-server-alias/
http://technet.microsoft.com/en-us/library/ms190445.aspx

SQL Server 2008: create trigger across all tables in db

Using SQL Server 2008, I've created a database where every table has a datetime column called "CreatedDt". What I'd like to do is create a trigger for each table so that when a value is inserted, the CreatedDt column is populated with the current date and time.
If you'll pardon my pseudocode, what I'm after is the T-SQL equivalent of:
foreach (Table in MyDatabase)
{
create trigger CreatedDtTrigger
{
on insert createddt = datetime.now;
}
}
If anyone would care to help out, I'd greatly appreciate it. Thanks!
As #EricZ says, the best thing to do is bind a default for the column. Here's how you'd add it to every table using a cursor and dynamic SQL:
Sure, You can do it with a cursor:
declare #table sysname, #cmd nvarchar(max)
declare c cursor for
select name from sys.tables where is_ms_shipped = 0 order by name
open c; fetch next from c into #table
while ##fetch_status = 0
begin
set #cmd = 'ALTER TABLE ' + #table + ' ADD CONSTRAINT DF_' + #table + '_CreateDt DEFAULT GETDATE() FOR CreateDt'
exec sp_executesql #cmd
fetch next from c into #table
end
close c; deallocate c
No need to go for Cursors. Just copy the result of below Query and Execute.
select distinct 'ALTER TABLE '+ t.name +
' ADD CONSTRAINT DF_'+t.name+'_crdt DEFAULT getdate() FOR '+ c.name
from sys.tables t
inner join sys.columns c on t.object_id=c.object_id
where c.name like '%your column name%'
Here's another method:
DECLARE #SQL nvarchar(max);
SELECT #SQL = Coalesce(#SQL + '
', '')
+ 'ALTER TABLE ' + QuoteName(T.TABLE_SCHEMA) + '.' + QuoteName(T.TABLE_NAME)
+ ' ADD CONSTRAINT ' + QuoteName('DF_'
+ CASE WHEN T.TABLE_SCHEMA <> 'dbo' THEN T.Table_Schema + '_' ELSE '' END
+ C.COLUMN_NAME) + ' DEFAULT (GetDate()) FOR ' + QuoteName(C.COLUMN_NAME)
+ ';'
FROM
INFORMATION_SCHEMA.TABLES T
INNER JOIN INFORMATION_SCHEMA.COLUMNS C
ON T.TABLE_SCHEMA = C.TABLE_SCHEMA
AND T.TABLE_NAME = C.TABLE_NAME
WHERE
C.COLUMN_NAME = 'CreatedDt'
;
EXEC (#SQL);
This yields, and runs, a series of statements similar to the following:
ALTER TABLE [schema].[TableName] -- (line break added)
ADD CONSTRAINT [DF_schema_TableName] DEFAULT (GetDate()) FOR [ColumnName];
Some notes:
This uses the INFORMATION_SCHEMA views. It is best practice to use these where possible instead of the system tables because they are guaranteed to not change between versions of SQL Server (and moreover are supported on many DBMSes, so all things being equal it's best to use standards-compliant/portable code).
In a database with a case-sensitive default collation, one MUST use upper case for the INFORMATION_SCHEMA view names and column names.
When creating script it's important to pay attention to schema names and proper escaping (using QuoteName). Not doing so will break in someone's system some day.
I think it is best practice to put the DEFAULT expression inside parentheses. While no error is received without it in this case, with it, if the function GetDate() is parameterized and/or ever changed to a more complex expression, nothing will break.
If you decide that column defaults are not going to work for you, then the triggers you imagined are still possible. But it will take some serious work to manage whether the trigger already exists and alter or create it appropriately, JOIN to the inserted meta-table inside the trigger, and do it based on the full list of primary key columns for the table (if they exist, and if they don't, then you're out of luck). It is quite possible, but extremely difficult--you could end up with nested, nested, nested dynamic SQL. I have such automated object-creating script that contains 13 quote marks in a row...

Need to add constraint containing table name to sql table using sp_MSforeachtable

I'm trying to use sp_MSforeachtable to add a new column to all my tables with a named constraint.
So far, I've done this:
USE [MYTable]
GO
exec sp_MSforeachtable 'ALTER TABLE ? ADD ChangedBy nvarchar(100) DEFAULT (suser_name()) NOT NULL'
That works except that the constraint name comes out something like: DF_TableName_Change_51EF2864
I want it to be named DF_TableName_ChangedBy
I've played around and found that PARSENAME(''?'',1) will give me the name of the table. Is there anyway to dynamically build the constraint name using this?
Example: ... CONSTRAINT ''DF_''+PARSENAME(''?'',1)+''_CreatedBy'' DEFAULT ...
(That doesn't seem to work but I included it to give a feel for what I'm hoping can be done.)
Thanks for any help!
It's a little cumbersome but you can do it by adding the column as nullable, adding the constraint, deciding what value you want to store for pre-existing rows, then making the column NOT NULL. I would also shy away from unsupported, undocumented stored procedures. I've discovered a problem with sp_MSforeachdb (with a workaround here) and it's possible this can manifest itself here as well. This is how I would accomplish this:
DECLARE #sql NVARCHAR(MAX);
SET #sql = N'';
SELECT #sql = #sql + CHAR(13) + CHAR(10) + N'ALTER TABLE '
+ QUOTENAME(SCHEMA_NAME([schema_id])) + '.'
+ QUOTENAME(name)
+ ' ADD ChangedBy NVARCHAR(100) NOT NULL;
ALTER TABLE ' + QUOTENAME(SCHEMA_NAME([schema_id])) + '.'
+ QUOTENAME(name) + ' ADD CONSTRAINT DF_' + name
+ '_ChangedBy DEFAULT (SUSER_SNAME()) FOR ChangedBy;
UPDATE ' + QUOTENAME(SCHEMA_NAME([schema_id])) + '.'
+ QUOTENAME(name) + ' SET ChangedBy = N''pre-existing'';
ALTER TABLE ' + QUOTENAME(SCHEMA_NAME([schema_id])) + '.'
+ QUOTENAME(name) + ' ALTER COLUMN ChangedBy NVARCHAR(100) NOT NULL;'
FROM sys.tables WHERE is_ms_shipped = 0;
PRINT #sql;
--EXEC sys.sp_executesql #sql;
(Change the comment when you trust that it is doing what you expect. Note that you may not see the entire command in the PRINT output; depending on the number of tables you have, it will likely get truncated. You can use TOP 1 or an additional WHERE clause against sys.tables to see what a single table's set of commands will look like.)
You could also simply rename the constraint afterward:
DECLARE #sql NVARCHAR(MAX);
SET #sql = N'';
SELECT #sql = #sql + CHAR(13) + CHAR(10)
+ N'EXEC sp_rename N''' + c.name + ''',N''DF_' + t.name
+ '_ChangedBy'', N''OBJECT'';'
FROM sys.default_constraints AS c
INNER JOIN sys.tables AS t
ON c.parent_object_id = t.[object_id]
WHERE c.name LIKE 'DF[_]%[_]Change[_]%'
AND LOWER(c.[definition]) LIKE '%suser%';
PRINT #sql;
--EXEC sys.sp_executesql #sql;
These scripts both assume you don't have silly object names, like 1 of My Friend's Cool High % Table!.

Accessing 400 tables in a single query

I want to delete rows with a condition from multiple tables.
DELETE
FROM table_1
WHERE lst_mod_ymdt = '2011-01-01'
The problem is that, the number of table is 400, from table_1 to table_400.
Can I apply the query to all the tables in a single query?
If you're using SQL Server 2005 and later you can try something like this (other versions and RDMS also have similar ways to do this):
DECLARE #sql VARCHAR(MAX)
SET #sql = (SELECT 'DELETE FROM [' + REPLACE(Name, '''','''''') + '] WHERE lst_mod_ymdt = ''' + #lst_mod_ymdt + ''';' FROM sys.tables WHERE Name LIKE 'table_%' FOR XML PATH(''))
--PRINT #sql;
EXEC ( #sql );
And as always with dynamic sql, remember to escape the ' character.
This will likely fall over if you have say table_341 which doesn't have a lst_mod_ymdt column.