I know that to find all the fields of a table I should use something like
sqlplus > desc testtable;
This lists all the fields of a table (here testtable)
But now, I have a list of tables in my database.
What is the way through which I can get the fields of all tables
in a given database using sqlplus?
I tried
sqlplus > desc <Databasename>; which didnot work.
Someone told me to use
sqlplus > select * from INFORMATION_SCHEMA.TABLES ; //gives error.
SQLPLUS > SELECT * FROM INFORMATION_SCHEMA.COLUMNS; //gives some error.
(At the bottom line, I am trying to get the database schema.)
I don't believe that the information_schema tables you can find in other dbs (SQL Server, PostGres, MySQL, etc) is in Oracle. I use to use the ALL_TAB_COLUMNS table to get at that type of information....maybe another alternative.
Link: ALL_TAB_COLUMNS
Related
With the release of dplyr 0.7.0, it is now supposedly easy to connect to Oracle using the odbc package. However, I am running into a problem accessing tables not inside the default schema (for me it is my username). For example, suppose there is the table TEST_TABLE in schema TEST_SCHEMA. Then, example SQL syntax to get data would be: select * from TEST_SCHEMA.TEST_TABLE'.
To do the same in `dplyr, I am trying the following:
# make database connection using odbc: [here's a guide][1]
oracle_con <- DBI::dbConnect(odbc::odbc(), "DB")
# attempt to get table data
tbl(oracle_con, 'TEST_SCHEMA.TEST_TABLE')
Now, this leads to an error message:
Error: <SQL> 'SELECT *
FROM ("TEST_SCHEMA.TEST_TABLE") "zzz12"
WHERE (0 = 1)'
nanodbc/nanodbc.cpp:1587: 42S02: [Oracle][ODBC][Ora]ORA-00942: table or view does not exist
I think the problem here is the double quotation marks, as:
DBI::dbGetQuery(oracle_con, "select * from (TEST_SCHEMA.TEST_TABLE) where rownum < 100;")
works fine.
I struggled with this for a while until I found the solution at the bottom of the introduction to dbplyr. The correct syntax to specify the schema and table combo is:
tbl(oracle_con, in_schema('TEST_SCHEMA', 'TEST_TABLE'))
As an aside, I think the issue with quotation marks is lodged here: https://github.com/tidyverse/dplyr/issues/3080
There are also the following alternate work-arounds that may be suitable depending on what you wish to do. Since the connection used DBI, one can alter the schema via:
DBI::dbSendQuery(oracle_con, "alter session set current_schema = TEST_SCHEMA")
after which tbl(oracle_con, 'TEST_TABLE') will work.
Or, if you have create view privileges, you can create a "shortcut" in your default schema to any table you are interested in:
DBI::dbSendQuery(oracle_con, "CREATE VIEW TEST_TABLE AS SELECT *
FROM TEST_SCHEMA.TEST_TABLE")
Note that the latter may be more suitable for applications where you wish to copy local data to the database for a join, but do not have write access to the table's original schema.
I want to know the equivalent query of Teradata BTEQ "create set table" in Snowflake SQL. I'm working on query conversion between BTEQ to Snowflake. Is there any direct syntax? If not, how can I create a set(Allows only unique values/records) table?
Snowflake doesn't have this functionality, and I don't know any database other than Teradata that does.
You can try to emulate that e.g. by always inserting data using a temporary staging table and then MERGE or INSERT..SELECT.., explicitly avoiding duplicates (on the loading side), or access the data through a view that does SELECT DISTINCT * FROM table.
I am getting this error while saving my data into the table. I have already created a 'product_Design' table in my database. I am using Sql Server 2008. Everything is working fine on local host but not on the server. I also tried to insert data in different tables and its working but I am just not able to insert data in this(product_Design) table ? I really need help regarding this thing.
here is my sql query
insert into z3ctjholo.dbo.product_Design values(#prodID, #productName, #designName, #designPath, #finalDesign, #front, #cont, #divHeight, GETDATE(), 0, 1)
I also tried this query
insert into product_Design values(#prodID, #productName, #designName, #designPath, #finalDesign, #front, #cont, #divHeight, GETDATE(), 0, 1)
Both the queries are generating error. Please help me out.
Thanks..
So finally i found what is the problem. if you ever face such kind of problem then execute this command in sql server and see whether your table is connected to any schema apart from dbo. Use this statement to check whether the table is connected to any other schema.
use yourDatabaseName
Then
SELECT * FROM INFORMATION_SCHEMA.TABLES
after that if you find that your table is connected with other schema apart from dbo then use your any statement like this
select * from schemaName.tableName
(eg. my schema name is z3ctjholo and my table name is product_Design)
so my statement would be like this
select * from z3ctjholo.product_Design
what i was doing wrong, i was using two schema names (z3ctjholo.dbo.product_Design).
I hope it will help someone..
Thanks...
There are two reasons, I can find so far.
1. Either the connection settings in web.config is incorrect.
2. your database is case sensitive collation and so check the name with case. May be you have created the table with name Product_Design and trying to insert in product_Design, in this case also, the command may not work.
Please check both the points.
I am running a SQLite database in memory and I am attempting to drop a table with the following command.
DROP TABLE 'testing' ;
But when I execute the SQL statement, I get this error
SQL logic error or missing database
Before I run the "Drop Table" query I check to make sure that the table exists in the database with this query. So I am pretty sure that the table exists and I have a connection to the database.
SELECT count(*) FROM sqlite_master WHERE type='table' and name='testing';
This database is loaded in to memory from a file database and after I attempt to drop this table the database is saved from memory to the file system. I can then use a third party SQLite utility to view the SQLite file and check to see if the "testing" exists, it does. Using the same 3rd party SQLite utility I am able to run the "Drop TABLE" SQL statement with out error.
I am able to create/update tables without any problems.
My questions:
Is there a difference between a memory database and a file database in SQLite when dropping a table?
Is there a way to disable the ability to drop a table in SQLite that I may have accentually turned on somehow?
Edit: It appears to have something to do with a locked table. Still investigating.
You should not have quotes in your DROP TABLE command. Use this instead:
DROP TABLE testing
I had the same problem when using Sqlite with the xerial jbdc driver in the version 3.7.2. and JRE7
I first listed all the tables with the select command as follows:
SELECT name FROM sqlite_master WHERE type='table'
And then tried to delete a table like this:
DROP TABLE IF EXISTS TableName
I was working on a database stored on the file system and so it seems not to effect the outcome.
I used the IF EXISTS command to avoid listing all the table from the master table first, but I needed the complete table list anyway.
For me the solution was simply to change the order of the SELECT and DROP.
Can any one tell me that how to get names of all tables of a database using asp.net
A newer method on SQL Server is to use the INFORMATION_SCHEMA Views to get the information:
SELECT table_name FROM INFORMATION_SCHEMA.Tables WHERE table_type='BASE TABLE'
This particular view also includes Views in its list of tables, which is why you need the where clause.
You didn't mention which database engine you are using. On SQL Server, you can query the sysobjects table and filter for objects with type U:
SELECT name FROM sysobjects WHERE type = 'U'
In case you are interested in the MySQL way to achieve this, you can use
DESCRIBE tableName;