SelectAdapter (IBM FHIR Server)

java.lang.Object
- com.ibm.fhir.database.utils.query.SelectAdapter

Direct Known Subclasses:

FromSubQueryAdapter
```
public class SelectAdapter
extends Object
```
An abstract representation of a select statement which can be translated into an executable select statement. Keeps track of bind variables (parameter markers) and hopefully is a bit easier to use (and is more reliable) than constructing SQL with StringBuilder. The goal is to support two main use-cases (which drive the API design):
- 1. Simplify construction of hand-written SQL statements
- 2. Support code-generated SQL where a statement is constructed from another model (e.g. FHIR search queries).
The goal isn't to enforce building a syntactically perfect SQL statement - checking that is the role of the RDBMS SQL parser. But hopefully this makes things a bit easier, less error-prone and therefore quicker. It also helps to standardize the SQL statement building process across the project.

Constructor Summary

Constructors
Constructor	Description
`SelectAdapter(boolean distinct, String... columns)`
`SelectAdapter(Select select)`	Adapter this select statement
`SelectAdapter(String... columns)`	Public constructor taking a collection of string column names

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`SelectAdapter`	`addColumn(String source, String name, Alias alias)`
`Select`	`build()`	Get the statement we've been constructing
`SelectAdapter`	`column(String source, String name)`
`FromAdapter`	`from()`	Create a `FromAdapter` associated with the current select statement.
`FromAdapter`	`from(Select sub, Alias alias)`	Add the sub-query select to the FROM clause
`FromAdapter`	`from(String table)`	Create a from clause for this select statement
`FromAdapter`	`from(String tableName, Alias alias)`	Create a from clause for this select statement
`Select`	`getSelect()`	Getter for the select statement we are managing
`void`	`pagination(int offset, int rowsPerPage)`	Add pagination offset/limit to the query

Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SelectAdapter
```
public SelectAdapter(Select select)
```
Adapter this select statement

Parameters:

select -

SelectAdapter
```
public SelectAdapter(String... columns)
```
Public constructor taking a collection of string column names

Parameters:

columns -

SelectAdapter

public SelectAdapter(boolean distinct,
                     String... columns)

Method Detail

column

public SelectAdapter column(String source,
                            String name)

addColumn

public SelectAdapter addColumn(String source,
                               String name,
                               Alias alias)

from

public FromAdapter from(String tableName,
                        Alias alias)

Create a from clause for this select statement

Returns:

from

public FromAdapter from(Select sub,
                        Alias alias)

Add the sub-query select to the FROM clause

Parameters:: sub - the sub-query select statement; alias -
Returns:

from
```
public FromAdapter from(String table)
```
Create a from clause for this select statement

Returns:

from
```
public FromAdapter from()
```
Create a FromAdapter associated with the current select statement. No row sources are added to the query. The FROM will only be added to the statement if rows sources are subsequently added to the returned FromAdapter.

Returns:

getSelect
```
public Select getSelect()
```
Getter for the select statement we are managing

Returns:

pagination
```
public void pagination(int offset,
                       int rowsPerPage)
```
Add pagination offset/limit to the query

Parameters:

translator -

offset -

rowsPerPage -

build
```
public Select build()
```
Get the statement we've been constructing

Returns: