I need the ability to add FTS3 to a sqlite3 table after it was created, not as it is created. Does anyone know the ALTER syntax to accomplish this?
SQLite does not support altering a table from a normal table to an FTS3 table. All you can do with ALTER TABLE is change the table name or add columns.
You will have to use CREATE VIRTUAL TABLE to make the FTS3 table and then copy the data.
Related
ALTER TABLE a add (OWNER_NAME VARCHAR2,OWNER_PARENT VARCHAR2);
Is it possible to alter table add MULTIPLE columns in a single statement in sqlite3?
The SQLite documentation provides the following picture to illustrate how the ALTER TABLE is understood by SQLite.
So, it does not seem possible to add multiple columns in a single ALTER TABLE command.
Reference: SQLite Query Language: ALTER TABLE
EDIT:
SQLite is a bit rigid when it comes to modifying existing tables and has limited support for the ALTER TABLE query.
Some more information can be found following this link: How do I add or delete columns from an existing table in SQLite.
The link also provides a workaround to carry out complex table modifications.
In a nutshell (emphasis mine):
If you want to make more complex changes in the structure of a table, you will have to recreate the table. You can save existing data to a temporary table, drop the old table, create the new table, then copy the data back in from the temporary table.
Is it possible to delete a column from an SQLlite database. I have Googled this and it seems to be impossible.
From the ALTER TABLE manual;
SQLite supports a limited subset of ALTER TABLE. The ALTER TABLE command in SQLite allows the user to rename a table or to add a new column to an existing table. It is not possible to rename a column, remove a column, or add or remove constraints from a table.
So, no, not without dropping and recreating the table.
According to the docs:
It is not possible to rename a column, remove a column, or add or
remove constraints from a table.
I guess it has to be done manually.
I want create table from another table with constraint?
I used this query "create table destination as select * from source;" fro table creation.
But its copy only the column name in table without column constraint.
There is a special table named sqlite_master, holding the full CREATE TABLE statement for each table (it's modified as appropriate during ALTER TABLE).
I would make my application retrieve that CREATE TABLE statement:
SELECT sql FROM sqlite_master WHERE type='table' AND name='source';
Then I would replace the table name right after CREATE TABLE tokens, and execute the result as a new sqlite query.
I don't think that it's possible to do in sqlite's pure SQL without extensions.
Can any one depict a simple example for using temporary tables in stored procedure for updating two tables in mysql?
Two kind of temporary tables available. One is session based and the other one is global temporary table.
Below is the simple example:
Select A,b,c into #MyTemp From MyDbTable
In the above example, #myTemp is the temporary table that you are creating. MyDbTable is the one that exist in your database. You can create multiple temporary tables.
I would suggest reading the article from here: Link
--Create a temp table and insert all these counts in it
Create Table #OperatorReportCount(Id int identity,Particulars varchar(100),NoOfArticles int)
--Insert these values in table
Insert Into #OperatorReportCount(Particulars,NoOfArticles) Values('Articles processed',#ProcessedArticleCount)
Insert Into #OperatorReportCount(Particulars,NoOfArticles) Values('Articles approved',#ArticlesApproved)
Insert Into #OperatorReportCount(Particulars,NoOfArticles) Values('Articles rejected',#ArticleRejectedCount)
Insert Into #OperatorReportCount(Particulars,NoOfArticles) Values('Rejections recieved',#RejectionsRecievedCount)
Insert Into #OperatorReportCount(Particulars,NoOfArticles) Values('Articles put on hold',#ArticlesOnHoldCount)
--Select the operator count table
Select Particulars,NoOfArticles From #OperatorReportCount
SQLite3 gives you a default primary key called rowid for each table if you don't specify a primary key. However, it looks like there are some disadvantages to relying on this:
The VACUUM command may change the ROWIDs of entries in tables that do not have an explicit INTEGER PRIMARY KEY.
http://www.sqlite.org/lang_vacuum.html
I want to alter an existing SQLite3 database to use explicit primary keys rather than implicit rowid's so I have the ability to run vacuum when necessary. Can I do this without rebuilding the whole database?
You don't need to rebuild the whole database. However since SQLite doesn't support ALTER TABLE statements you need to:
create a temporary table with the correct schema
copy all data from the original table to the temp table
delete the original table
rename the temp table
I suggest you use a app such as SQLiteman to do this for you.