I have a few tables in SQLite and I am trying to figure out how to reset the auto-incremented database field.
I read that DELETE FROM tablename should delete everything and reset the auto-incremement field back to 0, but when I do this it just deletes the data. When a new record is inserted the autoincrement picks up where it left off before the delete.
My ident field properties are as follows:
Field Type: integer
Field Flags: PRIMARY KEY, AUTOINCREMENT, UNIQUE
Does it matter I built the table in SQLite Maestro and I am executing the DELETE statement in SQLite Maestro as well?
Any help would be great.
Try this:
delete from your_table;
delete from sqlite_sequence where name='your_table';
SQLite Autoincrement
SQLite keeps track of the largest
ROWID that a table has ever held using
the special SQLITE_SEQUENCE table. The
SQLITE_SEQUENCE table is created and
initialized automatically whenever a
normal table that contains an
AUTOINCREMENT column is created. The
content of the SQLITE_SEQUENCE table
can be modified using ordinary UPDATE,
INSERT, and DELETE statements. But
making modifications to this table
will likely perturb the AUTOINCREMENT
key generation algorithm. Make sure
you know what you are doing before you
undertake such changes.
You can reset by update sequence after deleted rows in your-table
UPDATE SQLITE_SEQUENCE SET SEQ=0 WHERE NAME='table_name';
As an alternate option, if you have the Sqlite Database Browser and are more inclined to a GUI solution, you can edit the sqlite_sequence table where field name is the name of your table. Double click the cell for the field seq and change the value to 0 in the dialogue box that pops up.
If you want to reset every RowId via content provider try this
rowCounter=1;
do {
rowId = cursor.getInt(0);
ContentValues values;
values = new ContentValues();
values.put(Table_Health.COLUMN_ID,
rowCounter);
updateData2DB(context, values, rowId);
rowCounter++;
while (cursor.moveToNext());
public static void updateData2DB(Context context, ContentValues values, int rowId) {
Uri uri;
uri = Uri.parseContentProvider.CONTENT_URI_HEALTH + "/" + rowId);
context.getContentResolver().update(uri, values, null, null);
}
If you are working with python and you want to delete all records from some table and reset AUTOINCREMENT.
You have this table
tables_connection_db.execute("CREATE TABLE MY_TABLE_DB (id_record INTEGER PRIMARY KEY AUTOINCREMENT, value_record real)")
So if you had added some records
connection_db=sqlite3.connect("name_file.db")
tables_connection_db=connection_db.cursor()
tables_connection_db.execute("DELETE FROM MY_TABLE_DB ") # delete records
connection_db.commit()
name_table="MY_TABLE_DB"
tables_connection_db.execute("UPDATE sqlite_sequence SET seq=1 WHERE name=? ",(name_table,))
connection_db.commit()
connection_db.close()
Related
I have a table in Google Cloud Spanner.
CREATE TABLE test_id (
Id STRING(MAX) NOT NULL,
KeyColumn STRING(MAX) NOT NULL,
parent_id INT64 NOT NULL,
Updated TIMESTAMP NOT NULL OPTIONS (allow_commit_timestamp=true),
) PRIMARY KEY (Id)
And, I am trying to perform transaction.insert_or_update through a python script.
For each row in a pandas dataframe, I am doing:
transaction.insert_or_update(
'test_id', columns=['Id','KeyColumn', 'parent_id', 'Updated'],
values=[(uuid.uuid4().hex, row["KeyColumn"], row["parent_id"], spanner.COMMIT_TIMESTAMP)],
)
What I want is that if the row["KeyColumn"] is already present in KeyColumn of the table, update its parent_id column, otherwise insert a new row in the Spanner table corresponding to that KeyColumn.
But since, my primary key is Id which is generated randomly by uuid.uuid4().hex, it every time inserts a new row.
If I understand you correctly, the following is the situation:
ID is the primary key of your table.
There is a unique index defined for the table on the column KeyColumn.
You want to insert_or_update a row using KeyColumn as the column that should be used to determine whether the row already exists.
That is unfortunately not possible. insert_or_update will always use the primary key of the table to determine whether the row exists. I can think of three possible solutions to this problem, but they all have their drawbacks:
You could change the table definition and make KeyColumn the primary key and set a unique index on the Id column. The problem with this is of course that any other code that depends on Id being the primary key also needs to change. It is also a rather cumbersome change, because Cloud Spanner does not allow you to change the primary key of a table, so you would have to create a copy of the test_id table and then drop the old table.
You could fetch the row from Cloud Spanner before updating it by reading it using the KeyColumn value that you have. The big problem with this is obviously performance. You will need to do a read for each row that you want to update.
You could use a DML statement (UPDATE test_id SET parent_id=#parent WHERE KeyColumn=#key) to execute the update and check whether it actually updated a row by checking the returned update count. If it did not update anything, you could then execute the insert. This will obviously also be slower than an insert_or_update mutation.
Here there is a way to query the Cloud Spanner with a specific index.
You should use something like this in the end of your query : FROM test_id#{FORCE_INDEX=KeyColumnIndex} .
Even though this is the way to execute queries on secondary indexes and the answer for the question in the title, I do not know how much it can be applied in your use case.
I'm in the process of masking my ids from the url. I solved this by having a GUID in the URL instead of the primary key (which someone could easily guess). This GUID will map itself to the record just like a primary key.
Is this a decent solution? Someone would have to guess the GUID to see other people's data. Is there a security loophole I'm missing here.
How could I update my existing database to loop through records using PostgreSQL to update each record with a unique GUID?
You may also create the GUIDs without a Postgres extension, e. g.:
ALTER TABLE my_table ADD COLUMN guid UUID
DEFAULT MD5(RANDOM()::TEXT || ':' || CURRENT_TIMESTAMP)::UUID NOT NULL;
If you need not to define the GUID with a default value, you can use row data for the generation, the primary key for instance:
BEGIN;
ALTER TABLE my_table ADD COLUMN guid UUID;
UPDATE my_table SET guid = MD5(id::TEXT || ':' || CURRENT_TIMESTAMP)::UUID;
ALTER TABLE my_table ALTER guid SET NOT NULL;
END;
The uuid-ossp extension has functions for generating random uuids.
First:
create extension "uuid-ossp";
then:
alter table url add column guid uuid not null default uuid_generate_v4();
How do I set a column to increment automatically with Oracle SQL Developer? Why is the form disabled?
Note: The image shows the Data Modeler, but the question and top answer talk about editing an existing database.
If you want to make your PK auto increment, you need to set the ID column property for that primary key.
Right click on the table and select "Edit".
In "Edit" Table window, select "columns", and then select your PK
column.
Go to ID Column tab and select Column Sequence as Type. This will
create a trigger and a sequence, and associate the sequence to
primary key.
See the picture below for better understanding.
// My source is: http://techatplay.wordpress.com/2013/11/22/oracle-sql-developer-create-auto-incrementing-primary-key/
Unfortunately oracle doesnot support auto_increment like mysql does. You need to put a little extra effort to get that.
say this is your table -
CREATE TABLE MYTABLE (
ID NUMBER NOT NULL,
NAME VARCHAR2(100)
CONSTRAINT "PK1" PRIMARY KEY (ID)
);
You will need to create a sequence -
CREATE SEQUENCE S_MYTABLE
START WITH 1
INCREMENT BY 1
CACHE 10;
and a trigger -
CREATE OR REPLACE TRIGGER T_MYTABLE_ID
BEFORE INSERT
ON MYTABLE
REFERENCING NEW AS NEW
FOR EACH ROW
BEGIN
if(:new.ID is null) then
SELECT S_MYTABLE.nextval
INTO :new.ID
FROM dual;
end if;
END;
/
ALTER TRIGGER "T_MYTABLE_ID" ENABLE;
You can make auto increment in SQL Modeler. In column properties window Click : General then Tick the box of Auto Increment. After that the auto increment window will be enabled for you.
UPDATE: In Oracle 12c onward we have an option to create auto increment field, its better than trigger and sequence.
Right click on the table and select "Edit".
In "Edit" Table window, select "columns", and then select your PK
column.
Go to Identity Column tab and select "Generated as Identity" as Type, put 1 in both start with and increment field. This will
make this column auto increment.
See the below image
From SQL Statement
IDENTITY column is now available on Oracle 12c:
create table t1 (
c1 NUMBER GENERATED by default on null as IDENTITY,
c2 VARCHAR2(10)
);
or specify starting and increment values, also preventing any insert into the identity column (GENERATED ALWAYS) (again, Oracle 12c+ only)
create table t1 (
c1 NUMBER GENERATED ALWAYS as IDENTITY(START with 1 INCREMENT by 1),
c2 VARCHAR2(10)
);
EDIT : if you face any error like "ORA-30673: column to be modified is not an identity column", then you need to create new column and delete the old one.
#tom-studee you were right, it's possible to do it in the data modeler.
Double click your table, then go to the column section. Here double click on the column which will have the auto increment. In the general section there is a checkbox "autoincrement", just tick it.
After that you can also go to the "autoincrement" section to customize it.
When you save it and ask the data modeler to generate the SQL script, you will see the sequence and trigger which represent your autoincrement.
I found this post, which looks a bit old, but I figured I'd update everyone on my new findings.
I am using Oracle SQL Developer 4.0.2.15 on Windows.
Our database is Oracle 10g (version 10.2.0.1) running on Windows.
To make a column auto-increment in Oracle -
Open up the database connection in the Connections tab
Expand the Tables section, and right click the table that has the column you want to change to auto-increment, and select Edit...
Choose the Columns section, and select the column you want to auto-increment (Primary Key column)
Next, click the "Identity Column" section below the list of columns, and change type from None to "Column Sequence"
Leave the default settings (or change the names of the sequence and trigger if you'd prefer) and then click OK
Your id column (primary key) will now auto-increment, but the sequence will be starting at 1.
If you need to increment the id to a certain point, you'll have to run a few alter statements against the sequence.
This post has some more details and how to overcome this.
I found the solution here
Oracle doesn't have autoincrementing columns. You need a sequence and a trigger. Here's a random blog post that explains how to do it: http://www.lifeaftercoffee.com/2006/02/17/how-to-create-auto-increment-columns-in-oracle/
How to do it with Oracle SQL Developer:
In the Left pane, under the connections you will find "Sequences", right click and select create a new sequence from the context sensitive pop up. Fill out the details: Schema name, sequence_name, properties(start with value, min value, max value, increment value etc.) and click ok. Assuming that you have a table with a key that uses this auto_increment, while inserting in this table just give "your_sequence_name.nextval" in the field that utilizes this property.
I guess this should help! :)
Drag and drop your table from the left side menu into a worksheet and you will get a list of options. Pick "Insert" and then apply, and then done.
How do I auto increment the primary key in a SQL Server database table? I've had a look through the forum but can't see how to do this.
I've looked at the properties but can't see an option. I saw an answer where you go to the Identity specification property and set it to yes and set the Identity increment to 1, but that section is grayed out and I can't change the no to yes.
There must be a simple way to do this but I can't find it.
Make sure that the Key column's datatype is int and then setting identity manually, as image shows
Or just run this code
-- ID is the name of the [to be] identity column
ALTER TABLE [yourTable] DROP COLUMN ID
ALTER TABLE [yourTable] ADD ID INT IDENTITY(1,1)
the code will run, if ID is not the only column in the table
image reference fifo's
When you're creating the table, you can create an IDENTITY column as follows:
CREATE TABLE (
ID_column INT NOT NULL IDENTITY(1,1) PRIMARY KEY,
...
);
The IDENTITY property will auto-increment the column up from number 1. (Note that the data type of the column has to be an integer.) If you want to add this to an existing column, use an ALTER TABLE command.
Edit:
Tested a bit, and I can't find a way to change the Identity properties via the Column Properties window for various tables. I guess if you want to make a column an identity column, you HAVE to use an ALTER TABLE command.
You have to expand the Identity section to expose increment and seed.
Edit: I assumed that you'd have an integer datatype, not char(10). Which is reasonable I'd say and valid when I posted this answer
Expand your database, expand your table right click on your table and select design from dropdown.
Now go Column properties below of it scroll down and find Identity Specification, expand it and you will find Is Identity make it Yes. Now choose Identity Increment right below of it give the value you want to increment in it.
CREATE TABLE Persons (
Personid int IDENTITY(1,1) PRIMARY KEY,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Age int
);
The MS SQL Server uses the IDENTITY keyword to perform an auto-increment feature.
In the example above, the starting value for IDENTITY is 1, and it will increment by 1 for each new record.
Tip: To specify that the "Personid" column should start at value 10 and increment by 5, change it to IDENTITY(10,5).
To insert a new record into the "Persons" table, we will NOT have to specify a value for the "Personid" column (a unique value will be added automatically):
Perhaps I'm missing something but why doesn't this work with the SEQUENCE object? Is this not what you're looking for?
Example:
CREATE SCHEMA blah.
GO
CREATE SEQUENCE blah.blahsequence
START WITH 1
INCREMENT BY 1
NO CYCLE;
CREATE TABLE blah.de_blah_blah
(numbers bigint PRIMARY KEY NOT NULL
......etc
When referencing the squence in say an INSERT command just use:
NEXT VALUE FOR blah.blahsequence
More information and options for SEQUENCE
When you're using Data Type: int you can select the row which you want to get autoincremented and go to the column properties tag. There you can set the identity to 'yes'. The starting value for autoincrement can also be edited there. Hope I could help ;)
I had this issue where I had already created the table and could not change it without dropping the table so what I did was:
(Not sure when they implemented this but had it in SQL 2016)
Right click on the table in the Object Explorer:
Script Table as > DROP And CREATE To > New Query Editor Window
Then do the edit to the script said by Josien; scroll to the bottom where the CREATE TABLE is, find your Primary Key and append IDENTITY(1,1) to the end before the comma. Run script.
The DROP and CREATE script was also helpful for me because of this issue. (Which the generated script handles.)
You can use the keyword IDENTITY as the data type to the column along with PRIMARY KEY constraint when creating the table.
ex:
StudentNumber IDENTITY(1,1) PRIMARY KEY
In here the first '1' means the starting value and the second '1' is the incrementing value.
If the table is already populated it is not possible to change a column to IDENTITY column or convert it to non IDENTITY column. You would need to export all the data out then you can change column type to IDENTITY or vice versa and then import data back.
I know it is painful process but I believe there is no alternative except for using sequence as mentioned in this post.
Be carefull like if you want the ID elements to be contigius or not. As SQLSERVER ID can jump by 1000 .
Examle: before restart ID=11
after restart , you insert new row in the table, then the id will be 1012.
You could do the following: New Table Creation:
-- create new table with Column ID which is Primary Key and Auto Increment --
CREATE TABLE titles(
id INT NOT NULL IDENTITY(1,1) PRIMARY KEY, --Primary Key with Auto-Increment --
keyword VARCHAR(260),
status VARCHAR(10),
);
If you Table Already exists and need to make the changes to ID column to be auto-increment and Primary key, then see below:
ALTER TABLE table DROP COLUMN id; // drop the existing ID in the table
ALTER TABLE table ADD id int IDENTITY(1, 1) NOT NULL; // add new column ID with auto-increment
ALTER TABLE table ADD CONSTRAINT PK_ident_test PRIMARY KEY CLUSTERED (id); // make it primary key
using replication in sql srv causes the addition of this guid field, it also adds a value to it
but when i insert new records to the db, i have to give somthing or the guid field
it should be like aaaaa-aaa-something and unique!!
this is a problem for me , how am i supposed to do this keeping it unique every time?
should sql srv automatically add some yhing?
The ROWGUIDCOL added by Merge Replication should be populated with... guids:
ROWGUIDCOL does not enforce uniqueness
of the values that are stored in the
column and does not automatically
generate values for new rows that are
inserted into the table. To generate
unique values for each column, either
use the NEWID function on INSERT
statements or specify the NEWID
function as the default for the
column.