How can a persistent entity have an associated identifier but no representation in the database?
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I was reading Hibernate user guide when I came across the definition of a managed/persistent entity. It says:
managed, orpersistent
the entity has an associated identifier and is associated with a persistence context. It may or may not physically exist in the database yet.
I read somewhere else (some forum on the internet) that the difference between a detached entity and an transient is that a detached entity has an identifier associated with it which it gets from the database store when we make a representation of the entity. So if that is the case how can an entity have an associated identifier but no representation in the database if it has to first have a representation to get the identifier? Sorry if my question is not clear enough I will elaborate if you ask.
java hibernate jpa entity persistent
edited Nov 12 at 6:28
Slaw
6,1242830
asked Nov 12 at 6:19
kaka
85228
add a comment |
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0
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I was reading Hibernate user guide when I came across the definition of a managed/persistent entity. It says:
managed, orpersistent
the entity has an associated identifier and is associated with a persistence context. It may or may not physically exist in the database yet.
I read somewhere else (some forum on the internet) that the difference between a detached entity and an transient is that a detached entity has an identifier associated with it which it gets from the database store when we make a representation of the entity. So if that is the case how can an entity have an associated identifier but no representation in the database if it has to first have a representation to get the identifier? Sorry if my question is not clear enough I will elaborate if you ask.
java hibernate jpa entity persistent
edited Nov 12 at 6:28
Slaw
6,1242830
asked Nov 12 at 6:19
kaka
85228
The section of the guide you link also documents what atransientanddetatchedentity is. Thetransientdescription says: "It has no persistent representation in the database and typically no identifier value has been assigned (unless the assigned generator was used)".
– Slaw
Nov 12 at 6:36
An entity can have an id at the class level but no id at database level. it says "associated" identifier. the emphasis here is on the word association which I assumed it means the database level.
– kaka
Nov 12 at 6:53
A transient entity is still transient even though we assign an id annotation to one of its properties. the annotation makes no difference otherwise it would mean transient = detached. that means a managed/persistent entity with no id association in the database is a also a transient?
– kaka
Nov 12 at 6:58
An entity that has an associated identifier doesn't need to be represented in the database to get the associated identifier, think identifiers generated from sequences ...
– tom
Nov 12 at 15:27
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
I was reading Hibernate user guide when I came across the definition of a managed/persistent entity. It says:
managed, orpersistent
the entity has an associated identifier and is associated with a persistence context. It may or may not physically exist in the database yet.
I read somewhere else (some forum on the internet) that the difference between a detached entity and an transient is that a detached entity has an identifier associated with it which it gets from the database store when we make a representation of the entity. So if that is the case how can an entity have an associated identifier but no representation in the database if it has to first have a representation to get the identifier? Sorry if my question is not clear enough I will elaborate if you ask.
java hibernate jpa entity persistent
edited Nov 12 at 6:28
Slaw
6,1242830
asked Nov 12 at 6:19
kaka
85228
I was reading Hibernate user guide when I came across the definition of a managed/persistent entity. It says:
managed, orpersistent
the entity has an associated identifier and is associated with a persistence context. It may or may not physically exist in the database yet.
I read somewhere else (some forum on the internet) that the difference between a detached entity and an transient is that a detached entity has an identifier associated with it which it gets from the database store when we make a representation of the entity. So if that is the case how can an entity have an associated identifier but no representation in the database if it has to first have a representation to get the identifier? Sorry if my question is not clear enough I will elaborate if you ask.
java hibernate jpa entity persistent
java hibernate jpa entity persistent
edited Nov 12 at 6:28
Slaw
6,1242830
asked Nov 12 at 6:19
kaka
85228
edited Nov 12 at 6:28
Slaw
6,1242830
asked Nov 12 at 6:19
kaka
85228
edited Nov 12 at 6:28
Slaw
6,1242830
edited Nov 12 at 6:28
Slaw
6,1242830
edited Nov 12 at 6:28
Slaw
6,1242830
6,1242830
asked Nov 12 at 6:19
kaka
85228
asked Nov 12 at 6:19
kaka
85228
asked Nov 12 at 6:19
kaka
85228
85228
The section of the guide you link also documents what atransientanddetatchedentity is. Thetransientdescription says: "It has no persistent representation in the database and typically no identifier value has been assigned (unless the assigned generator was used)".
– Slaw
Nov 12 at 6:36
An entity can have an id at the class level but no id at database level. it says "associated" identifier. the emphasis here is on the word association which I assumed it means the database level.
– kaka
Nov 12 at 6:53
A transient entity is still transient even though we assign an id annotation to one of its properties. the annotation makes no difference otherwise it would mean transient = detached. that means a managed/persistent entity with no id association in the database is a also a transient?
– kaka
Nov 12 at 6:58
An entity that has an associated identifier doesn't need to be represented in the database to get the associated identifier, think identifiers generated from sequences ...
– tom
Nov 12 at 15:27
add a comment |
The section of the guide you link also documents what atransientanddetatchedentity is. Thetransientdescription says: "It has no persistent representation in the database and typically no identifier value has been assigned (unless the assigned generator was used)".
– Slaw
Nov 12 at 6:36
An entity can have an id at the class level but no id at database level. it says "associated" identifier. the emphasis here is on the word association which I assumed it means the database level.
– kaka
Nov 12 at 6:53
A transient entity is still transient even though we assign an id annotation to one of its properties. the annotation makes no difference otherwise it would mean transient = detached. that means a managed/persistent entity with no id association in the database is a also a transient?
– kaka
Nov 12 at 6:58
An entity that has an associated identifier doesn't need to be represented in the database to get the associated identifier, think identifiers generated from sequences ...
– tom
Nov 12 at 15:27
The section of the guide you link also documents what a
transient and detatched entity is. The transient description says: "It has no persistent representation in the database and typically no identifier value has been assigned (unless the assigned generator was used)".– Slaw
Nov 12 at 6:36
The section of the guide you link also documents what a
transient and detatched entity is. The transient description says: "It has no persistent representation in the database and typically no identifier value has been assigned (unless the assigned generator was used)".– Slaw
Nov 12 at 6:36
An entity can have an id at the class level but no id at database level. it says "associated" identifier. the emphasis here is on the word association which I assumed it means the database level.
– kaka
Nov 12 at 6:53
An entity can have an id at the class level but no id at database level. it says "associated" identifier. the emphasis here is on the word association which I assumed it means the database level.
– kaka
Nov 12 at 6:53
A transient entity is still transient even though we assign an id annotation to one of its properties. the annotation makes no difference otherwise it would mean transient = detached. that means a managed/persistent entity with no id association in the database is a also a transient?
– kaka
Nov 12 at 6:58
A transient entity is still transient even though we assign an id annotation to one of its properties. the annotation makes no difference otherwise it would mean transient = detached. that means a managed/persistent entity with no id association in the database is a also a transient?
– kaka
Nov 12 at 6:58
An entity that has an associated identifier doesn't need to be represented in the database to get the associated identifier, think identifiers generated from sequences ...
– tom
Nov 12 at 15:27
An entity that has an associated identifier doesn't need to be represented in the database to get the associated identifier, think identifiers generated from sequences ...
– tom
Nov 12 at 15:27
add a comment |
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The section of the guide you link also documents what a
transientanddetatchedentity is. Thetransientdescription says: "It has no persistent representation in the database and typically no identifier value has been assigned (unless the assigned generator was used)".– Slaw
Nov 12 at 6:36
An entity can have an id at the class level but no id at database level. it says "associated" identifier. the emphasis here is on the word association which I assumed it means the database level.
– kaka
Nov 12 at 6:53
A transient entity is still transient even though we assign an id annotation to one of its properties. the annotation makes no difference otherwise it would mean transient = detached. that means a managed/persistent entity with no id association in the database is a also a transient?
– kaka
Nov 12 at 6:58
An entity that has an associated identifier doesn't need to be represented in the database to get the associated identifier, think identifiers generated from sequences ...
– tom
Nov 12 at 15:27