Xbasic

SQL::TableInfo Class

Description

Functions for inspecting information about tables.

Discussion

The SQL::TableInfo object returns information about a database table. It can be useful when importing data from or exporting data to back-end tables. The easiest way to get a SQL::TableInfo object is to use the SQL::Connection::GetTableInfo() method. The following code was run in the Interactive window.

dim conn as SQL::Connection
dim ti as SQL::TableInfo

' Define the connection string and open the connection.
? conn.open("{A5API=Access,FileName='C:\Program Files\a5v8\MDBFiles\Alphasports.mdb',UserName='Admin'}")
= .T.

' Get the TableInfo
? conn.GetTableInfo(ti, "customer")
= .T.

Note that the SQL::TableInfo object is passed as an argument, along with the name of the table to investigate.

Properties and methods of the SQL::TableInfo object are listed below.

Properties

XMLCharacter

The schema in XML format.

TableTypeSQL::TableType

An enumerated type describing the table type.

TableTypeNameCharacter

This is the displayable name of the enumeration value in TypeName.

? tt.TableType 
= -1
? tt.TableTypeName 
= "Invalid"
tt.tabletype 
= View
? tt.TableType 
= 1
? tt.TableTypeName 
= "View"

CatalogCharacter

Catalog property

SchemaCharacter

Schema property

OwnerCharacter

The database user or group that owns the table.

TableNameCharacter

TableName property

UniqueNameCharacter

A concatenation of the owner (if any) and name properties.

NameCharacter

The unique name of the table. The table must be unique for the owner, but need not be globally unique.

NativeAPICharacter

The name of the API active when this object was created.

NativeSyntaxCharacter

The name of the syntax at the time the object was created.

CommentCharacter

The comment stored for the table, if the database supports it.

AliasCharacter

Alias property

UpdateableLogical

True (.T.) if the table is updatable.

CanUpdateInTransactionLogical

If a table has a large text or binary column and the database can not cache updates for multiple rows, this value will be false.

SizeToFitLogical

When set to true, . DBFRowSyntax will return lengths adjusted based on the actual data. Notes:

Call .UpdateStatistics() before getting the DBFRowSyntax. If the longest column is zero length, the default length is 15. SizeToFit will limit the size of inserted or updated fields on imported or linked tables to the maximum size of the previous values.

SelectRowLimitNumeric

Defaults to -1 (no limit). This property is used when generating select statements to limit the number of rows retrieved.

SelectRowStartingOffsetNumeric

SelectRowStartingOffset property

LastKnownRowCountNumeric

Set by calling .UpdateStatistics().

DBFRowSyntaxCharacter

The DBFRowSyntax property shows how to define a DBF table with the same columns and data as the source database.

? ti.Name
= "customer"
? ti.Updateable
= .T.
? ti.NativeSyntax
= "Access"
? ti.DBFRowSyntax
= CUSTOMER_ID,N,10,0
FIRSTNAME,C,20,0
LASTNAME,C,20,0
COMPANY,C,32,0
PHONE,C,20,0
FAX,C,20,0
BILL_ADDRESS1,C,40,0
BILL_ADDRESS2,C,40,0
BILL_CITY,C,20,0
BILL_STATE_REGION,C,20,0
BILL_POSTAL_CODE,C,10,0
BILL_COUNTRY,C,20,0
SHIP_ADDRESS1,C,40,0
SHIP_ADDRESS2,C,40,0
SHIP_CITY,C,20,0
SHIP_STATE_REGION,C,20,0
SHIP_POSTAL_CODE,C,10,0
SHIP_COUNTRY,C,20,0
SHIP_SAME,L,1,0
EMAIL,C,60,0

PrimaryKeyExpressionCharacter

The subscript value to use when referencing the Index property to access the primary key index. If there is no primary key defined, this property will have a value of -1. If the value is an integer greater than or equal to 1, the primary key may be accessed using the syntax IndexPrimaryKeySubscript.

PrimaryKeySubscriptNumeric

PrimaryKeySubscript property

IdentityColumnSubscriptNumeric

Returns the index of the column which is auto-increment or identity (-1 if none).

QueryAliasCharacter

This is an advanced property used to get more information about a column.

The QueryAlias property is only populated when a query object ( SQL::Query, SQL::Statement, etc.) is validated. After calling SQL::Query::Validate, the query object has a SQL::ResultSet object (no data, just definitions). The TableInfo property of the SQL::ResultSet is an array of SQL::TableInfo objects that describe the tables in the FROM clause (this is used by the query genie to map select list columns to the source table definition to get more information about the actual column.

dim q as sql::query
dim c as sql::connection
?c.open("{a5api=access,filename=c:\northwind.mdb,user=admin}")
= .T.
?q.parse("select * from customers cust")
= .T. 
?q.validate(c) 
= .T. 
?q.resultset.tableinfo1.queryalias 
= "cust"

ColumnSQL::IndexColumnInfo[]

An array of index column ( SQL::IndexColumnInfo ) definitions.

IndexSQL::IndexInfo[]

An array of index ( SQL::IndexInfo ) definitions.

IdentitySequenceNameCharacter

IdentitySequenceName property

ActiveLinkDBFRowSyntaxCharacter

ActiveLinkDBFRowSyntax property

Methods

AddColumn Method: Add a Column.
AddIndex Method: Add a Index.
Clear Method: Reset the contents of the TableInfo as if it had just been declared.
Clone Method: Create a copy of an object instance.
ColumnIsInPrimaryKey Method: Checks if a specified column is part of a table's primary key.
ColumnNumber Method: Get the index of a Column from the name.
DeleteColumn Method: Delete a Column.
DeleteIndex Method: Delete a Index.
IndexNumber Method: Get the index of a Index from the name.
InsertColumn Method: Insert a new Column.
InsertIndex Method: Insert a new Index.
ListColumns Method: Create a list of the table columns (optionally including types).
MoveColumn Method: Move a block of Column items.
MoveIndex Method: Move a block of Index items.
ParseTableName Method: Parse a dot separated table name and return the components. Use brackets [] to wrap names with dots in them.
UpdateStatistics Method: Gather statistical information about the actual table.