Update links

Author: kabilar

docs/src/concepts/data-model.md

@@ -108,7 +108,7 @@ DataJoint comprises:
 
 - a schema :ref:`definition <definitions>` language
 - a data [manipulation](../manipulation/index.md) language
-- a data [query](../query/query-objects.md) language
+- a data [query](../query/principles.md) language
 - a [diagramming](../design/diagrams.md) notation for visualizing relationships between 
 modeled entities
 

docs/src/manipulation/insert.md

@@ -74,7 +74,7 @@ In such cases, data can be [fetched](../query/fetch.md) from the first table and
 inserted into another table, but this results in transfers back and forth between the 
 database and the local system.
 Instead, data can be inserted from one table into another without transfers between the 
-database and the local system using [queries](../query/query-objects.md).
+database and the local system using [queries](../query/principles.md).
 
 In the example below, a new schema has been created in preparation for phase two of a 
 project.

docs/src/manipulation/transactions.md

@@ -6,7 +6,7 @@ interrupting the sequence of such operations halfway would leave the data in an
 state. 
 While the sequence is in progress, other processes accessing the database will not see 
 the partial results until the transaction is complete.
-The sequence make include [data queries](../query/query-objects.md) and 
+The sequence make include [data queries](../query/principles.md) and 
 [manipulations](index.md).
 
 In such cases, the sequence of operations may be enclosed in a transaction. 

docs/src/query/operators.md

@@ -1,6 +1,6 @@
 # Operators
 
-[Data queries](query-objects.md) have the form of expressions using operators to derive 
+[Data queries](principles.md) have the form of expressions using operators to derive 
 the desired table.
 The expressions themselves do not contain any data.
 They represent the desired data symbolically.