In this overload first parameter is name of a collection, and second parameter is the array of restrictions to be applied when querying information. These restrictions specify which subset of the collection will be returned. The restrictions can include, for example, the database name (in this case, only collection elements belonging to this database will be returned) or the mask for the name of collection elements (only the elements satisfying this mask will be returned). The quantity and description of restrictions allowed for each metadata collection are represented in the table here. Their number can also be obtained from the return of the GetSchema() method. If the second parameter is null/Nothing, it is ignored.
Instead of specifying the metadata collection name as a string constant, you may use members of System.Data.DbMetaDataCollectionNames and Devart.Data.PostgreSql.PgSqlMetadataCollectionNames as the first GetSchema argument values. The members of these classes are the string fields, each field stores the corresponding metadata collection name. It is recommended to use these fields rather than manually input the collection names manually as the string constants because in case of using these fields, you will find misspellings at compile-time, and intellisense will show you all the available metadata collection names.
GetSchema Method Reference
GetSchema supports two kinds of wildcards: "%" and "_". These special characters behave exactly as in LIKE operator. "%" means zero or more of any characters, "_" means any single character.
When calling the GetSchema method, you can pass all or few of restrictions, applicable to the chosen collection. In the latter case, you have to put "%" wildcard in the place of omitted restriction, if it must be specified before the restriction you want to apply. For example, GetSchema("Casts", new string[] { "%", "%", "date" }) returns list of all casts to type "date". Or, suppose you want to query all functions within a certain schema: GetSchema("Functions", new string[] { "%", "public" }) returns list of all functions in schema public. Note that this collection may accept 8 restrictions, however, you do not need to specify all of them.
The following table provides detailed information on metadata collections that can be retrieved using the GetSchema method, and restrictions that can be applied for them. Some collections may be not supported in older server versions. If you try to get metadata for unsupported collection you will get exception with message "Collection not defined".
Collection Name
| Number of restrictions |
Remarks
|
---|---|---|
MetaDataCollections | 0 |
Returns this list. Same as using GetSchema() method without parameters.
|
ReservedWords | 0 |
Lists all reserved words used in the server.
|
AggregateFunctions | 2 |
GetSchema("AggregateFunctions") returns detailed list of all aggregate functions on the server.
|
Arguments | 5 |
GetSchema("AggregateFunctions") returns the list of the function arguments. The following restrictions may be specified:
|
Casts | 3 |
GetSchema("Casts") returns list of casts available on the server.
|
Columns | 3 |
Returns list of columns, their schema, table, type, and some extra information.
|
Databases | 3 |
Returns list of databases on the server.
|
DatasourceInformation | 1 |
Returns information about data sources.
The only restriction is schema name.
|
Domains | 9 |
Returns list of domains on the server. The restrictions for this collection are the following:
|
ForeignKeys | 4 |
Returns list of foreign keys on the server. The restrictions for this collection are the following:
|
Functions | 8 |
Returns list of functions on the server. The following restrictions may be specified:
|
Groups | 1 |
Lists all groups on the server, including IDs and members.
The only restriction is a group name.
|
Indexes | 4 |
Returns list of indexes and their details. Restricted by:
|
Languages | 2 |
Lists all languages on the server.
The first restriction is a language name, the second is OID.
|
NestedTables | 5 |
Lists nested tables on the server. Restricted by:
|
Operators | 2 |
Returns list of operators allowed on the server.
Restrict it by OID and name.
|
PrimaryKeys | 3 |
Returns list of primary keys on the server.
|
Schemas | 2 |
Returns list of schemas on the server.
|
Tables | 4 |
Returns list of tables on the server. Restrict the collection with:
|
Triggers | 6 |
Returns list of triggers on the server. Restricted by:
|
Types | 5 |
Returns list of types on the server. Restricted by:
|
Users | 1 |
Lists all users on the server.
When restricted by username, returns information about specific user.
|
Views | 4 |
Returns list of types on the server. Restricted by:
|
Npgsql 集合:
MetaDataCollections
Restrictions
Databases
Tables
Columns
Views
Users
https://github.com/npgsql/Npgsql/releases/tag/v2.2.4.3
http://npgsql.projects.pgfoundry.org/docs/api/Npgsql.NpgsqlConnection.GetSchema_overloads.html
http://www.codeproject.com/Articles/37154/PostgreSQL-PostGis-Operations
数据类型:
bit | System.Int64 | 1560 |
varbit | System.Int64 | 1560 |
bit varying | System.Int64 | 1560 |
bool | System.Boolean | 16 |
boolean | System.Boolean | 16 |
smallint | System.Int16 | 21 |
int | System.Int32 | 23 |
integer | System.Int32 | 23 |
int4 | System.Int32 | 23 |
serial | System.Int32 | 23 |
serial4 | System.Int32 | 23 |
bigint | System.Int64 | 20 |
int8 | System.Int64 | 20 |
bigserial | System.Int64 | 20 |
serial8 | System.Int64 | 20 |
float | System.Single | 700 |
real | System.Single | 700 |
float4 | System.Single | 700 |
double | System.Double | 701 |
double precision | System.Double | 701 |
decimal | System.Decimal | 1700 |
numeric | System.Decimal | 1700 |
dec | System.Decimal | 1700 |
date | System.DateTime | 1082 |
timestamp | System.DateTime | 1114 |
timestamptz | System.DateTime | 1184 |
time | System.TimeSpan | 1083 |
timetz | System.TimeSpan | 1266 |
interval | System.TimeSpan | 1186 |
char | System.String | 1042 |
character | System.String | 1042 |
uuid | System.Guid | 2950 |
varchar | System.String | 1043 |
character varying | System.String | 1043 |
text | System.String | 25 |
binary | System.Byte[] | 17 |
bytea | System.Byte[] | 17 |
cidr | System.String | 29 |
circle | System.String | 718 |
inet | System.String | 869 |
line | System.String | 628 |
lseg | System.String | 601 |
macaddr | System.String | 829 |
box | System.String | 603 |
path | System.String | 602 |
point | System.String | 600 |
polygon | System.String | 604 |
money | System.Double | 790 |
集合:
MetaDataCollections |
ReservedWords |
AggregateFunctions |
Arguments |
Casts |
CompositeTypeAttributes |
Columns |
DataSourceInformation |
DataTypes |
Databases |
Domains |
ForeignKeys |
ForeignKeyColumns |
Functions |
Groups |
Indexes |
Indexcolumns |
Languages |
NestedTables |
Operators |
OperatorClasses |
PrimaryKeys |
Rules |
Schemas |
Sequences |
Tables |
Triggers |
Types |
Users |
UserPrivileges |
UniqueKeys |
Views |
Restrictions |
Postgresql NpgsqlDbType System.DbType Enum .Net System Type
---------- ------------ ------------------ ----------------
int8 Bigint Int64 Int64
bool Boolean Boolean Boolean
bytea Bytea Binary Byte[]
date Date Date DateTime
float8 Double Double Double
int4 Integer Int32 Int32
money Money Decimal Decimal
numeric Numeric Decimal Decimal
float4 Real Single Single
int2 Smallint Int16 Int16
text Text String String
time Time Time DateTime
timetz Time Time DateTime
timestamp Timestamp DateTime DateTime
timestamptz TimestampTZ DateTime DateTime
interval Interval Object TimeSpan
varchar Varchar String String
inet Inet Object IPAddress
bit Bit Boolean Boolean
uuid Uuid Guid Guid
array Array Object Array